YOU SAID:

There once was someone in a thing that did a thing

INTO JAPANESE

あることをしたことの中に誰かがいたことがあります

BACK INTO ENGLISH

There was someone in what I did

INTO JAPANESE

私がしたことに誰かがいました

BACK INTO ENGLISH

Someone was doing what I did

INTO JAPANESE

誰かが私がしたことをしていました

BACK INTO ENGLISH

Someone was doing what i did

INTO JAPANESE

誰かが私がしたことをやっていた

BACK INTO ENGLISH

Someone was doing what I did

INTO JAPANESE

誰かが私がしたことをしていました

BACK INTO ENGLISH

Someone was doing what i did

INTO JAPANESE

誰かが私がしたことをやっていた