My thoughts for Sphinx's other powers to definitely involve illusions, but I was considering lowkey "force" telekinesis just so that he had a more tactile combat power. But I suppose it's not necessary. When in other people's minds, he wouldn't hijack them as much as he would "reshape" them to suit his purposes. He's a fan of inducing extremely-precise amnesia; even to himself. When he lets loose, though, he can basically mind-crush someone. His moniker comes from one of his earliest battles, in which out of desperation he forced a villain to forget how to breathe, asphyxiating him.

Osiris' name is subject to change; just need to find something suitable in Egyptian mythology. Current reference is a bit too benevolent. My thought as the "token evil" character is that he wormed his way onto whatever "council" that the heroes of the Citadel form. That actually brings up a few questions that I'm curious about.

Firstly, what is the governing body of the Citadel like? A council like I just suggested? A committee of various subdivisions? A structured hierarchy? Some details would be good.

Also, for about how long have metahuman phenomena existed? I have plans for Sphinx to have been bullied and outcast as a child due to his telepathy.