Essentially, there are few elements to a working interface:
- sending a message to the correct actor:
- that class needs to implement that interface, and function / event:
However:
I do not see a point in doing . You’ve already sent a message, why bother with applying damage? Add data to the interface instead.
Not saying there is no point or that it wouldn’t work, just that I am not seeing it 
You may have your reasons, ofc.