YOU SAID:

He who fights with monsters should look to it that he himself does not become a monster

INTO JAPANESE

モンスターと戦う者は自分自身がモンスターにならないように見なければならない

BACK INTO ENGLISH

Those who fight monsters must look like they do not become monsters themselves

INTO JAPANESE

モンスターと戦う人は、モンスター自体にならないように見える必要があります

BACK INTO ENGLISH

People who fight monsters need to look like they do not become monsters themselves

INTO JAPANESE

モンスターと戦う人は、自分自身でモンスターにならないように見える必要があります

BACK INTO ENGLISH

People who fight monsters need to look like they do not become monsters themselves