YOU SAID:

its been so long since i last have seen my son lost to this monster to the man behind the slaughter (aww man)

INTO JAPANESE

私の息子が虐殺の背後にいる男（aww man）にこのモンスターに負けたのを最後に見たのはとても長いことです

BACK INTO ENGLISH

It's been a long time since I last saw my son lose to this monster to the man behind the massacre.

INTO JAPANESE

私の息子が虐殺の背後にいる男にこの怪物に負けているのを最後に見たのは久しぶりです。

BACK INTO ENGLISH

It's been a long time since I last saw my son lose to this monster to the man behind the massacre.