Whos fault is it that someone ? question for UK/EU/US people.?

Question

If you where walking home and someone attacked you and you had never seen them before in your life and you pulled out a pen knife and the attacker got hurt but lived whos fault would it have been?.

Who is to blame and why?. hypothetically speaking that is.

From a laws point of view who would be to blame.

My question is aimed at american people and people who live in the EU

Answer 1

It would be my fault that the attacker lived.

Answer 2

The fault would ultimately be in the initial attacker.  Any action taken after that could be defended as self defense; however, to legally use the self defense defense the force used cannot be greater than initial force exerted.  Meaning, the initial attack was hand to hand combat, you pulled a knife; therefore, you then become an attacker.  Ultimately it would come down to whether or not the District Attorney would press charges (which is probably not), if they decide to it would go to trial and be up to a jury.  A jury would be unlikely to convict the victim for any wrong doing unless there were extreme circumstances.