Queen was part of Ace's own Royal Flush Gang. She battled the Justice League and was defeated by Doctor Light. But when Ace's death stripped Queen's powers, she reverted to her normal form — that of a middle aged man.
Powers and abilities
Queen gained enhanced strength as a result of Ace's reality-warping.
His design was clearly based upon the Queen of Hearts from Disney's Alice in Wonderland.
Just like his teammates, Queen's conception bears a specific in-joke: Upon reverting to his normal form, he is revealed to be a man, thus a "drag queen".