Talk:I'm the One/@comment-27382868-20160507230012/@comment-26397825-20160528033450

His dad was an assassin. There's a line earlier in the song that says "a murderers son". And in the episode "Beginning of the End" Emerald syays this:

Emerald: (getting up from her stance) That's... the assassin?

when Mercury shows Cinder and Emerald the body of Marcus Black. Cinder then asks Mercury if he is anything like his father, and he joins their team.