Until death

It's said that when you kill in self defense, it's not murder.

I think that I'm having issues with defining "self defense".

What is it when you kill someone who is making you want to kill yourself, rather than exist another minute on the same planet with that person?

What is it when you kill someone who will completely destroy your life, making it a living hell until that person chooses to stop?

What about when someone is a part of you? Is it not then self defense to kill someone who is torturing that person?


Yes, issues.