If I fight alone, do I hit more than three people, even if a few of those three people die, I don't need to bear criminal responsibility?

Either your life and property are not seriously threatened, or you have the ability to control the situation;

Or even if someone annoys you, you have the ability to get out of trouble;

You should bear the corresponding criminal responsibility.

If, under threat, you have nowhere to run and the other party has not stopped infringing, then it is self-defense.