@SaarebasSure you wanna do it in the future instead of in normal day? We can't vs any real known baddies or heroes if it is. Just say the original teen titans never formed. I mean, your not missing any heroes of note that can't just be somewhere else anyway. Cyborg got into the justice league, Robin is with Batman still, and Starfire/Raven/BB are either just not there or with their teams. (Comic versions of those might as well not exist/shouldn't exist anyway. A total 180 from the 2000s show.)
Could also just do Young Justice sorta stuff and have no limits there. Maybe even more setting flexibility?
@Saarebas Well, I had two idea's for characters, one only works in a future setting, the other is a witch that takes on the appearance of a 13 year old girl, because she hates the fact that all heroines have to be tall, busty bombshells. The Women of the Justice League having a "Supermodels only" rule and they refused to let her in unless she took on the form of an adult. She promptly flipped Red Tornado the bird before telling him that she liked him better when he was a big fat lady.
Ok, it wasn't actually like that, but she likes to say it like that.
But, yeah, she is essentially a fun-loving witch that loves children and always loves to take on their form. But, is about 500+ years old.
Ha, Light and her might have a fun little chat if she brings all that up. Shame I still don't got a picture of her to show everyone, but she kinda fits that mold a little, besides the monster sized hands, pointed legs, giant cartoony head with oversized eyes, and all that. xD