2. If the murder weapon is his, if you cut him with his murder weapon, you will intentionally hurt him and bear criminal responsibility; Unless the other party picks up the murder weapon and will hurt you, and you hurt him in the process of self-defense, it can be considered as self-defense.
3, but if your defense exceeds the necessary limit, it is excessive defense, and you still have to bear the corresponding responsibilities.
4. If the other person harasses you and you hurt him with a murder weapon, it is undoubtedly intentional injury and you should bear criminal responsibility.
The best way is to protect your legitimate rights and interests through legal channels.