YOU SAID:
he was certainly the son of evil
INTO JAPANESE
彼は確かに悪の子であった
BACK INTO ENGLISH
he was certainly a child of evil
INTO JAPANESE
彼は確かに邪悪な子供であった
BACK INTO ENGLISH
he was certainly an evil child
INTO JAPANESE
彼は確かに邪悪な子供だった
BACK INTO ENGLISH
he was certainly an evil child
That didn't even make that much sense in English.