Dealing Damage to Another Character

[AlonzoMachiraju]

Create an Apply Damage node, then drag from the As AICharacter pin to the Damaged Actor input on the Apply Damage node. Delete the SET node at the rightmost end of your graph and drag the execution pin to ApplyDamage. Set Damage Causer on Apply Damage to self. Hopefully that will work.

Here is more information on damage in UE4:

Damage in Unreal Engine 4

The following is a related question on damage and blueprints that links to another:

How do I apply damage to the player?