in that case i would use something like the following.
for the weapon i would do your trace then get the hit actor and apply damage. in the example below i checked to make sure there was a hit and made sure it was a character.
then in all your characters you would have a script like the below picture. for this you would use the event any damage which gets incoming damage from the apply damage node. then you take the damage incoming and subtract it from the current health then set health. i also included a little death check.
this all makes it so you dont need a specific reference to damage something. your basically saying i want to apply damage to that thing over there without caring what the thing is. then the thing can decide how to handle the incoming damage. this also makes it easier to implement things like shields.