Udo's D10 Roleplaying System
This is a set of rules designed for a pen and paper roleplaying game, which is – in short – a form of social entertainment where a group of players experiences through the actions of fictional characters an interactive story being told by another person, also called the game master (GM). Since this is a barebones rulebook we'll assume that you are familiar with the concept of roleplaying games. If you are not, Google is your friend!
UD10 is supposed to be a very bare-bones and simple rulebook for (almost) any kind of roleplaying scenario. While simple in nature, it is also designed to allow the GM and players enough freedom of expression to play a rich and nuanced game.
The rules are also avaiable on GitHub, and are
licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Determining success and failure
One of the fundamental principles of this set of rules is the die roll with a d10 (ten-sided die), to perform an action which is called a check. Checks are done in order to determine the success or failure of an action a character is performing. Checks are performed with a rating. The rating is a value that describes how good a character is at doing something (the higher the better). How high this rating is for various checks will be described later. The d10 result rolled plus the character's rating determines the result of the check. A die roll result of 1 is always considered a failure. A die roll of 10 is always repeated and the results get added together.
When several characters or NPCs interact, often two or more rolls need to be compared against each other to determine a winner. In this case, the roll with the highest end result wins. If a draw occurs during combat, the defender wins.
Actions have varying degrees of difficulties. To reflect that, the GM (usually) announces the minimum result a player must roll to succeed beforehand. You can use the following table as a reference when it comes to determine the difficulty of a check:
A monkey could do it: 5 Easy task: 10 Normal task: 15 Difficult task: 20 Nearly impossible: 25+
To create a new character, distribute 5 points among the four attributes STR, DEX, CON, and INT - the highest rating of any attribute may be 3. Quick Start
What Are Attributes?
Each character has a simple set of properties that describe her on a basic level: Strength (STR), Dexterity (DEX), Constitution (CON), and Intelligence (INT). The higher the score of an attribute, the better developed it is. Attributes start at a rating of 0 points each at the time a character is created.
For example, say a character called Rebecca the Ranger has the following attributes:
STR: 2, DEX: 4, CON: 3, INT: 2
These values mean that Rebecca is first and foremost a very dextrous character. She typically excels at tasks that build on this attribute, such as shooting ranged weapons, climbing, dodging, and everything else where good coordination is of advantage.
Rolling Checks Against a Single Attribute
Attributes describe the basic characteristics of a person or entity. They are represented by a numerical rating starting from 0. To check whether a specific action that depends on an attribute succeeds or fails, roll a d10 and add the attribute. Compare the result to the difficulty number for the given task.
Checks Against Two or More Attributes
There are times when two attribute ratings need to be considered for an action. In this case just add the values of the attributes together. The GM decides what difficulty rating will apply to the check (see Difficulties).
Character Health Status
Starting at 10 points each, distribute 5 more points total among the health status scores HP, EP, and MS giving no more than 3 additional points to a single score. Quick Start
What Are The Status Scores?
The current status of a character is represented by the status scores: Hit Points, Endurance Points, and Mental Stability Points. Each of the three describes a certain aspect of the character's current health. Status Scores start at a rating of 10 points each at the time of character creation.
Hit Points (HP)
Injury and death: If the number of HP reaches zero, the character is severely injured. For any HP below zero, the character incurs a penalty of 1 to all her checks. Sustaining an injury that brings the character to zero or less HP does not automatically make the character unconscious, but for most intents and purposes results in incapacitation.
Falling below a HP value of -10 usually results in death, depending on the nature of the injury and other factors as determined by the GM.
Endurance Points (EP)
For each point below 0, the character sustains a penalty of 1 on all checks that require physical work or mental alertness. A characters EP rating cannot drop below -10.
Mental Stability Points (MS)
For each point below 0 MS points, the character is subject to a penalty of 1 on all checks that require mental coordination. A characters MS rating cannot drop below -10.
Health Status Summary
The Character Health Scores are: Hit Points (HP), Endurance Points (EP), and Mental Stability Points (MP). While any of those health scores can be reduced temporarily during the course of an adventure, more serious trauma can also result in permanent loss.
When creating a new character you get 10 points for skills. Select any skills from the list below and distribute these points among them. Do not give more than 3 points to a single skill. Quick Start
Alternatively, you may use a Skill Template that contains a number of pre-selected skills.
What Are Skills?
Like attributes, skills describe the character's capabilities. While there are only four attributes to signify the character's basic properties, skills can vary widely in number and ratings to represent the learned or innate special abilities of a person. Every character knows at least the Standard skills. Then, further skills can be acquired both at the time of character creation and later in the game. Every skill starts with a rating of 1.
Rolling Skill Checks
Making skill checks is similar to checking against attributes.
Skills usually correspond to an attribute, indicating that this attribute boosts the performance of that particular skill. The corresponding attribute to each skill is given in parentheses, like this:
Some Cool Skill [INT]To roll a skill check, add the skill's rating to the corresponding attribute rating, then roll a d10 and add this, too. The sum of these points is the result of the skill check. The GM will tell a player what minimum result is needed for the action to succeed.
Adding the D10's result of 5 to the skill's rating of 3 and the DEX attribute of three, Rebecca only manages an 11. The task is not successful and Rebecca is seen by her adversaries as she tries to enter the compound undetectedly.
Skill description headers may contain other tags besides the skills corresponding attribute in parentheses. Those tags help you identify specific properties of the skill at one glance. Here is a list of possible tags:
Skills tagged "untrained" can be performed even by characters who do not possess the skill at all. For the purpose of the individual skill check against such a skill, it is assumed that the character has a rating of zero. However, the corresponding attribute still counts when the check is made.
Some skills are exhausting for the character to use. Unless otherwise stated, successfully performing a skill marked "fatigue" causes the character to lose 1 EP.
A specialization skill is rarely used on its own, but commonly serves to provide a bonus to a certain other skill it is derived from. Specialization ratings cannot be higher than the rating of their parent skills.
Pool type skills are not skills in their own right, but provide a pool of bonus points that can be applied to certain other skill checks. Players can decide to apply one or more points from a pool to these checks as they see fit, however those points are then spent and have to be regenerated over time. Usually, combat skill pools are regenerated between skirmishes.
List of Skills
The GM is free to invent lots of additional skills as appropriate, so the following list is just an obvious preselection. check rolls against the special skills are made at the discretion of the GM. The skills listed here are intended for contemporary or near-future world settings.
Melee Combat Skills
The rating of this skill cannot be higher than the character's normal hand-to-hand combat skill.
The Hand-to-hand combat skill can also be used to determine the outcome of other non-combat-related hand-to-hand coordination tasks.
this is 10 for small weapons, 15 for medium weapons, and 20 for large weapons. For modern automatic weapons,
the difficulty rises by 5 points to load a cartridge into the chamber (but switching the safety off is free).
Readying a shield in addition to a melee weapon also raises the difficulty by 5.
The GM is free to apply additional situational modifiers. If the check is unsuccessful, the maneuver takes up
a normal action.
Ranged Combat Skills
This skill covers the attack with the character's off hand. It is possibly to attack with both hands at once, incurring a penalty of -2 on both checks.
The rating of this skill cannot be higher than the character's normal ranged combat skill.
Making a Character
This section describes how to quickly create a character. If you want to play one of the UD10 settings, you should refer to the character creation rules there.
1 - First, write down the 4 attributes: STR, DEX, CON, and INT. All of those have a rating of zero points. You may now distribute 5 points among those, but no single attribute may be higher than 3.
2 - Now it's time for the health status scores: HP, EP, or MS. They start at 10 each. You may distribute another 5 points among those, but no more than 3 points per status score.
3 - You probably want to decide beforehand what your character is supposed to be like. Decide on a job, or any stereotype you might want to realize here. Keep this in mind when distributing your points. You can refer to the stereotypical dispositions further down on this page.
4 - While it is up to the GM to decide how many points you get to spend in order to create your character, you now normally get 10 points to buy skills. Each point gets you a new skill or raises an existing skill by 1. To ensure new characters are balanced, no skill may exceed a rating of 3 during character creation though.
Here is a list of dispositions that may fit your character, you may choose one from each category:
Templates are pre-fabricated archetypes that can be applied to your character, depending on the setting you're playing in.
Choosing a template will cost a number of points that you would otherwise spend on acquiring skills.
A template will contain a set of bonuses to attributes and skills that your character gets to start with.
Bonus points from templates are applied after the freely assignable experience points for character generation are spent.
What templates are available depends on the setting you want to play in (the same applies to the selection of skills). In this part of the rulebook, we supply a few templates for making characters suitable for a contemporary, non-fantasy setting - in other words: templates for people you can find on any street today.
Contemporary Archetypes (Examples)
(Cost: 9)Intelligence Analyst
(Cost: 9)Law Enforcement Officer
(Cost: 9)Medical Doctor
(Cost: 9)Office Drone
(Cost: 8)PoliSci Student
(Cost: 6)Political Activist
(Cost: 9)Research Scientist
(Cost: 8)Security Guard
(Cost: 7)Social Worker
(Cost: 9)Sport Student
(Cost: 8)Street Thug
Making Your Own Templates
Templates are a good way to emulate the classical "character classes" found in many roleplaying systems. To encourage players to base their characters on a template while still giving them complete freedom, the point sums provided by templates are a bit cheaper than they would be if you created a similar character from scratch. As a rule of thumb, add the skill points of a template together, then add the double of all attribute bonus points and take 75% of the resulting sum as the cost for that template:
Template cost = [(sum of skill points) + (2 x sum of attribute bonuses)] * 0.75
Combat in UD10 can be played with varying levels of detail, as deemed appropriate by the GM. While this set of rules contains instructions for play with a combat map to visualize the position of characters and their surroundings, it is not a required accessory for the execution of meaningful combat scenes.
When To Do Combat
The main usage of a combat system is certainly to provide a rule framework for any kind of conflict scenario where force is being used. But because of the combat system's rules and mechanisms for tracking and handling spacial, temporal and physics-related game scenarios, it can also be appropriate for other situations that are not in the strictest sense combat-related. Ultimately, the GM decides whenever combat mode is to be used.
Generally speaking, UD10 tries to be "realistic" in a sense that combat is often a deadly endeavor for player characters and NPCs alike. In this, as in all other things, GM discretion is advised to bend the combat rules to whatever style of gameplay is preferred.
Before a fight can be played out, the GM needs to know the relevant stats for all NPCs that are going to be involved in the situation. This may require a short period of preparation if those characters are being designed on demand. Preparing NPCs stats or even generic templates for entire categories of similar NPCs will alleviate this need.
Also, before combat starts, the topography and the relative position of all parties needs to be determined by the GM. To avoid confusion at this point, it can be helpful to always keep track of party formation during the normal course of play – so the positions of the player characters are clear once a combat breaks out.
If you are using a battle map, this is the time to place the units (characters, machines, opponents) on the map. For the purpose of this instruction we will assume a standard combat grid map where each square represents a 1.5m wide zone that can hold one normally sized being.
Starting a Combat Round
It is important to understand that much of the combat rules revolve either directly or indirectly around the concept of representing a causal progression of events in time. For this purpose, the defining unit of measurement is the Combat Round. A Combat Round is a granular amount of time where actions can be performed by all combatants, it is the metric and the heartbeat of combat. In personal melee and ranged battles, a Combat Round correlates loosely to about 10 seconds of time. The GM may modify this amount in accordance to the specific needs of the situation (for example, sea battles with large vehicles should take a much larger amount of time per Combat Round). A battle or skirmish can last for any number of Combat Rounds. The GM determines when to start Combat Round mode and also when to drop out of it.
As the GM announces the start of a new Combat Round, the temporal order of actions is determined first. For this purpose, an Initiative roll is performed by all parties. The GM may decide to roll INI once for all NPCs, each group of NPCs, or even every NPC by herself. To determine Initiative, a d10 is rolled, and the skill rating of the Initiative skill is added. The entity with the highest result opens the round, after that, the character with the next lowest result can act, and so forth – until everyone has performed their actions. When a Combat Round is finished, the GM announces the next round.
For speedier gameplay, all characters involved in the last Combat Round should keep their rolled INI results and carry them over to subsequent rounds instead of re-rolling them every time.
Courses of Action
Unless situational reasons dictate otherwise, a character can do the following things each round:
- performing an action
- performing a reaction
- performing one or more free actions (within reasonable limits)
Once per combat round, a character can move. There are different types of movement available:
Instantaneous: these moves do not require much time and can be executed instantly and without having an effect on the other actions the character may perform during that round. Examples for instantaneous actions are: moving a single step (1 field on the map), looking around, dropping a weapon.
Standard Movement: a character can do a Standard Movement that does not take up all of her time and energy this round. When chosing this mode of movement, the character can still perform another action immediately either before or after moving. Standard movement involves: jumping over a medium-sized obstacle, walking, drawing a small weapon. The range of a character's standard movement is usually 5 meters plus her STR attribute.
Full Movement: when in full movement, the character cannot perform any other actions this round. During this mode, the character may move up to two times as far as her standard movement distance per round.
Free actions are minor maneuvers that don't prevent the character from performing their main action this round. Examples for free actions would be:
- exchanging a few words with someone
- moving one step
- making a hand signal
In addition to a standard movement, every combatant can perform one action per combat round. An action is any short activity
that can be performed nearly instantly, such as:
- attacking an opponent
- drawing and readying a weapon
- reloading a ranged weapon
- using or manipulating an item or tool
- performing a skill action that can be completed within the combat round
The most common type of action during a combat round is the attack action. There are two different types of attack actions: hand-to-hand and ranged attacks.
To perform an attack action, the appropriate skill check has to be successful. Additional modifiers to the skill are common, depending on the weapon's attack modifier („AM“) and other situational modifiers. If the skill check isn't successful against a given difficulty, it is assumed that the attack missed its target. The attack skill check's difficulty is calculated as follows:
opponent's Defense rating +/- modifiersNormally, an opponent has a Defense rating 10 plus her DEX attribute. However, the DEX attribute only applies when the attack can be anticipated. As such, it does not apply when the opponent is suprised, attacked from behind, or otherwise unable to foresee the move.
Defense Rating Modifiers (Examples)
|has a shield||+2|
|immobilized||-2 and DEX doesn't count|
|large in stature||-1|
|small in stature||+1|
Attack Modifiers (Examples)
|Melee Combat: opponent on higher ground||-2|
|Ranged Combat: after taking aim for 1 round||+2|
|Ranged Combat: after taking aim for 2 rounds||+4|
|Ranged Combat: bad visibility (i.e. fog)||-2|
|Ranged Combat: opponent is crouching||-2|
|Ranged Combat: opponent is moving||-2|
|Ranged Combat: shooting while moving||-4|
Ranged attacks require an appropriate ranged weapon. A check against the Ranged Combat skill is performed to determine whether the attack hits its target.
When making a ranged attack roll, it is also important to know how far away the target is. Every ranged weapon has a designated range increment.
Targets within that range can be attacked normally. If a target is beyond this range, a cumulative one point penalty applies for every time the range increment is exceeded.
Some ranged weapons can fire multiple shots during one attack. In this case, those alternative firing modes and their damage codes are described in the appropriate weapons table in the “Equipment” section.
Reactions and Defense
Parrying and Dodging
If the attack is successful, the GM determines whether the opponent is eligible for a Parry attempt or whether it is maybe possible to dodge the attack. To Parry, a character has to have an appropriate weapon ready – also, only one Parry attempt per combat round is permitted under normal circumstances. Parry is a skill that is linked to the DEX attribute, so a character who does not have this skill can try to Parry by rolling an untrained check against his DEX rating.
A Parry attempt is a comparative check. If the parry check's result is higher than the attack roll's result, the attack did not go through.
In certain situations, a character may have the option of using her environment for cover against enemy attacks. In this case, the GM assigns a cover rating depending on the situation. The cover is a bonus to the character's defense rating.
In general, such modifiers are called the character's defense rating. Armor, shields and other circumstances may also influence this value.
Optional Rule: Body Zones
If an attack on a character is successful, a roll needs to be made to determine which part of his body was hit by the attack so the corresponding protective effect of any armor can be applied. In order to do this, a d10 is used:
Determining The Damage
The next thing we need to know is the amount of damage caused by the attack. Every weapon has a damage code that tells us how to roll and calculate the damage points per attack. When not using the body zones, armor protection is averaged from all body zones into one single statistic. Damage codes are weapon-specific and usually contain a fixed amount of points plus a number of ten-sided dice. Whenever a ten comes up on a damage roll, the die may be rolled again and the result is added up.
If the victim of the attack has any protection or armoring, the amount of damage is lessened by the Armor rating of the respective body zone that was hit.
Optional Rule: Buffer
Most armor protects their wearer not only from immediate physical harm due to penetrating injuries but also ameliorates the effects of forceful impact. They have a characteristic called the buffer. Incoming damage is first lessened by the armor rating, and the rest - up to and including the buffer value of the armor - is converted into endurance point (EP) loss. The victim only sustains damage to her HP when the buffer of the armor is exceeded.
Next, the amount of damage of an attack is first lowered by the rating of the CON attribute. The remaining damage value is subtracted from the character's current Hit Points.
Summary: Taking Damage
- roll the weapon damage
- subtract the armor rating
- optional: subtract the buffer, lessen victim's EP by that amount
- subtract the victim's CON attribute
- lessen the victim's HP by the remaining value
Optional Rule: Armor Penetration
Some weapons are better at overcoming armor than others. This can be expressed by the optional penetration score of a weapon. Armor is then made less effective by the penetration score of an attacker's weapon. If you're playing with the optional buffer rule, the weapon's penetration score is also subtracted from the buffer's value.
Optional Rule: Fleeing From Battle
If a character turns their back and runs away from one or more melee combatants with whom she is currently engaged in combat, every one of those opponents gets an immediate free action to attack the fleeing character.
Optional Rule: Retreat
Instead of fleeing from a hand-to-hand combat situation, a character may also retreat during movement. Opponents do not get a free attack action when a character is retreating, however, doing the retreat costs a full round during which the character may do nothing else in order to successfully disengage from melee combat.
Weapons And Equipment Guide
This equipment guide is intended for contemporary scenarios. Equipment lists for futuristic, historical, or sword & sorcery backgrounds will be supplied when the respective settings modules come out. In the mean time, GMs can easily improvise their own equipment if needed. As with everything else in the rulebook, this is merely a suggestion.
Some kinds of melee weapons are easier to handle than others. The Attack Modifier (AM) value indicates
a bonus or penalty to the character's Melee Combat skill when using a given weapon.
Melee weapons are categorized by the damage type they deal. In this list, we have blunt, slashing, piercing, and crushing weapons.
Blunt weapons are considered non-lethal during normal use. They deal their damage not to the characters Hit Points, but her Endurance Points (EP) instead. In addition to that, they cause half that damage to HP.
Crushing weapons are good against older types of rigid armor such as hardened leather or armor plates. These types of armor are one point less efficient when dealing with crushing weapons.
Piercing weapons have more impact against opponents wearing mesh-like protection, such as chain mail; these types of armor are one point less efficient against piercing weapons.
Slashing weapons deliver the full inertia of the weapon through a very sharp edge. They cause one additional point of damage when attacking an opponent with no armor.
|(Unarmed Attack)||0||D5 + STR|
|Baton||0||D10 + STR||-1|
|Bayonet||-4||D10 + STR|
|Dagger / Long Knife||-4||D10 + STR|
|Flail||-4||D10 + STR*3|
|Long Sword||-4||D10 + STR*3|
|Longstaff||0||D10 + STR*2||-1|
|Mace||0||D10 + STR*2|
|Rapier||0||D10 + STR||+1|
|Short Sword||0||D10 + STR*2|
The following weapons are generic contemporary ranged weapons without any specific model description. The GM is welcome to use this general table to design specific firearm models that match their historic counterparts more accurately. "AM" is the attack modifier of the weapon. Damage refers to the damage caused by a firing mode. If a weapon has more than one firing mode, the damage ratings are separated by commata. Range refers to the designated range increment of the weapon (see also "range" under combat). Rifle-type weapons have a second range increment value which refers to the effective range increment if the weapon is mounted on a tripod or rests on the ground as the user is in a mostly immobile firing position - however the AM is lowered in this mode if the target is moving. "Short" and "long" refer to the ammunition expended during a short or long burst.
|Assault Rifle||-2||D10+4||+2||10m/30m||5, 20, or 30||3||10|
|Rifle||-2||D10+4||+2||10m/40m||5, 20, or 30|
|Shotgun (double barrel)||+2||D10+10-distance||-1||3m||2||2|
|Sniper Rifle||-4||D10+6||+3||10m/50m||1, or 5|
|Submachine Gun||-||D10+1||3m||15, 30||3||10|
Many modern military weapons are capable of full automatic firing modes. Mapped to the table above, the handguns and the rifle are also available as full automatic variants.
Rapid fire: Semi-automatic weapons or full automatic weapons switched to single-shot mode can be fired in rapid succession. This allows the user to shoot twice per combat round if they do not perform a movement action in the same round.
Short burst: Automatic weapons which have a short burst capability (denoted by the "Short" column above), can fire as many bullets in a single attack as stated. The attack is made with a penalty of -2. For every 2 points the attack roll comes above the target's defense rating, an additional bullet hits (up to the number of bullets fired).
Long burst: Automatic weapons which have a long burst capability (denoted by the "Long" column above), can fire as many bullets in a single attack as stated. The attack is made with a penalty of -4. For every 2 points the attack roll comes above the target's defense rating, an additional bullet hits (up to the number of bullets fired). An attacker can also choose to spread the long burst attack evenly among a group of up to three targets that are close to each other.
Suppression fire: An attacker can use this action to lay down suppression fire in order to keep a group of targets from leaving their cover positions. Suppression fire uses up the number of bullets equal to the long burst firing mode of the weapon. Until the attacker's next action in the coming combat round, every person who threatened by the shooter must make a morale check or reflexively take cover. If someone does emerge from cover, the attacker makes an automatic attack roll to hit them with a single bullet as a free action.
Armor is available for different body zones. The "penalty" value below refers to a penalty on all acrobatic actions (including melee combat) when wearing the armor.
|Full Plate Armor||6||6||-6|
*: Chain mail does not provide protection against ranged weapons.
Flash lights are essential outdoor survival gear that allows the user to project a cone of light at will. Flash light
Night vision goggles or night vision binoculars enable the user to see under extreme low-light conditions. Passive night vision
By attaching a targeting laser onto a ranged weapon, the attacker gains a +2 bonus to her attack roll. Targeting laser
Some weapons can be fitted with an optical targeting scope. When using the scope to attack, the weapon's range increments are doubled. Targeting scope
Getting and Spending Experience Points
Experience points are used by the GM to reward player characters. How much XP a character gets over time is
for the GM to decide. Several models are thinkable. The simplest one would be to award a fixed amount of
points after a gaming session (for example 3 points per character). You can also make XP a function of time
played (for example giving them 1 point for every hour of gaming) or employ your own scheme that takes into
account how the characters did overcome specific challenges.
By spending these experience points (XP), the players can increase their characters' attributes, health status scores, and skill ratings during the character's lifetime. As it gets harder to progress further in an area, it costs more XP to do so.
To raise an attribute by one point, spend XP equal to the new rating of the attribute, times three.
Acquiring a New Skill
Count the number of skills where the character currently has a rating of 1 or more, times two, this will be the cost of acquiring a new skill. Note that this cost does not apply when a character is being created, only when the character progresses later during the game this cost is applied.
Raising a Skill Rating
To raise a Skill rating by one point, spend XP equal to the new rating of the Skill.
Raising HP, EP, MS
To raise a Health Status score by one point, spend a number of XP equal to the new score.