There is currently a major bug in the game where casting a spell in Play-In-Editor causes the game to crash to a Package-PlayInEditor() bug. If you wish to test the game in PIE, you must do the following... 1.) Open BP_Spellbook, ArenaCharacter, SpellDataTable, SpellInfoStruct, and ALL spells found within the Spells folder 2.) Go into BP_Spellbook, go to the SpawnActor found within the FinishCastingFunc function, right click the node, and refresh it. This step isn't always necessary, but sometimes the editor will crash if you try to cast a spell.
If you do not wish to go through this, you must launch the game in Standalone mode.
I apologize for the inconvenience, but it is currently unclear as to what is causing the crash.
WASD are your movement controls. B opens your spellbook. I opens your inventory.