Stacking

Every Ragnarok Card stack its effects with itself in an additive form if put in different item slots.

For example, the cave spider card gives a 4% chance to poison the enemy. So if you have 2 of those in different slots, you have a 8% chance of poisoning.

In the same way, the zombie card gives 20% additional damage against the undead. So if you have 2 of those in different slots, you have 40% more damage.