How to make Enemy Die from My Sword Slash + How to make Character Die when HP hits Zero?

Ok, so I am trying to make my reapers die from my character attacking with his sword. But I don’t know how. Meaning, my character has an animation where he slashes his swords, and I want the sword slash to kill the enemy. Not a projectile or the character touching the enemy and it vanishes off the face of the Earth…if you can help with this that would be great!
Also, I can’t figure out how to make it so when the character’s HP hits Zero, the Character is “Destroyed”.
Here is a link to my game: http://flowlab.io/game/view/509671