Having a big name hero on a superhero team book has obvious advantages. It helps a publisher establish a “shared universe” concept by showing different characters with little actually in common hanging out. It provides some prestige to the team book by showing a popular character in the group. Readers who are on a budget can get one book with many heroes hanging around. It makes a lot of sense.
For creators, it’s another story. Having the big name hero on a book often limits what a creative team on the team book can do. If there’s a big announcement that some hero will die in a big storyline, a reader can take comfort knowing the death will not be the star of his own ongoing solo series, particularly if said series hasn’t been canceled yet. The death will more likely go to a character that only appears on that team and no where else. As such, many creators will add original characters to team books to have someone they can play around with.
That would be why we have characters like Empress.

Young Justice began as something of a junior Justice League for characters that were at the time maybe considered too young to join the Teen Titans, though a number would eventually end up on the Teen Titans anyway. After a one shot special or two, the book began with a three hero line-up of Robin (Tim Drake version), Superboy, and Impulse under the guidance of mentor the Red Tornado. As written by one of my favorite superhero writers Peter David, with clean art from Todd Nauck, the third issue saw the addition of three female heroes: Wonder Girl, Arrowette, and Secret.
Now, of the six founders, four team members (Robin, Impulse, Superboy, and Wonder Girl) were either stars of their own solo books or heavily associated with another hero and as such, David and Nauck could only do so much with them. For example, Robin specifically could only come out at night according to the Batman editors. That left Red Tornado, Arrowette, and Secret for David as writer to play with a bit more, and who knows? Red Tornado and Arrowette were each theoretically claimable for other books. However, for the sake of argument, the creative team only had full control over Red Tornado, Arrowette, and Secret, and David for one took as much advantage of that as he could.
Eventually that meant adding characters. Supporting characters were one thing, like a pair of federal agents from the All-Purpose Enforcement Squad (APES) known as Fite ‘n Maad, or, more accurately, Donald Fite and Ishido Maad.
If these sorts of name puns bother you, #1, Peter David’s sense of humor on this book may not be for you, and #2, we got a doozy coming up soon, so hold on.
As it was, Fite ‘n Maad didn’t really like the idea of juvenile superheroes and would act as something of a reoccurring roadblock to the team. They were both highly competent agents; they just didn’t think kids should put on costumes and fight crime.
Naturally, one of them had a kid who developed superpowers and decided to join the team to fight crime. That would be Fite’s daughter Anita.
Yes, her name was Anita Fite.
Sorry.
Anyway, Anita had two basic powers: teleportation and low level mind control. She could make weak-minded folks follow basic tasks. And that teleportation thing started early.

See, Anita learned a lot about voodoo as it was passed down from her mother and grandmother. Her mom had been murdered by a bad guy, leaving her nonbeliever father Donald as a single parent. He’d later be killed himself, but thanks to some general screwiness, both of Anita’s parents would eventually be reborn as babies for her to care for.
But before that could happen, we had Anita as a new superhero. She took the name Empress, which made sense since she was a master of the Emperor’s Stick, a baton with a pair of small swords stashed inside of it. Using her powers and a costume of her own, she joined Young Justice after an extensive interview process and background check.

So, really, here was another character David and Nauck could have mostly free reign on. If they wanted to have a juvenile Lobo clone sometimes called Slobo try to romance her, they could.

Of course, the other side of a character like Empress is, if the team book ends or the original creative team moves on, she’s likely to be pushed aside and forgotten. David and Nauck stayed on Young Justice to the end, with the series concluding and leading to most of that team joining a new Teen Titans line-up. Less flashy characters like Arrowette, Secret, Slobo, and Empress all went away, some with a proper send-off, others without. She may appear here and there, but not enough to get her onto a new team. Heck, she wasn’t included on the Young Justice animated series either, and that show managed to get most of the comic book team onto the show at least once.

Still, characters like Empress will no doubt continue to appear and will continue to disappear as long as team books with popular members exist.
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