The only history I know for him his is interaction through M'gann in Young Justice, when she gave him a blood transfusion to save his life.  Beyond that and his small role in Season 2 of YJ, I don't have much to offer you I'm sorry to say Tack.<br/><br/>Speaking of Ace, Raven and Artemis probably don't have much of a history do they?  She's been around the other heroes sure, but Raven didn't stick around after her request was turned down, so I doubt Artemis made much effort to get to know her really.  Nevermind, forget I said anything, unless you want to talk about it further.