YOU SAID:

we trained him wrong, as a joke

INTO JAPANESE

我々は冗談として、彼は間違って訓練を受けました

BACK INTO ENGLISH

We as a joke, he had received the wrong training

INTO JAPANESE

私たちは冗談として、彼は間違って訓練を受けていました

BACK INTO ENGLISH

We as a joke, he had received the wrong training