YOU SAID:

I had to kill him in self defense

INTO JAPANESE

私は自己防衛のために彼を殺さなければならなかった

BACK INTO ENGLISH

I had to kill him in self-defense.

INTO JAPANESE

私は自己防衛のために彼を殺さなければならなかった。

BACK INTO ENGLISH

I had to kill him in self-defense.