Steve felt for both Stiles and Julian in this situation. It was definitely awkward, but he had experience with it from Stiles' perspective with Harry looking so much like Tony. Steve hadn't needed more than a minute with Harry to believe that it wasn't Tony, although it also wasn't in Tony's nature to pretend to be someone he wasn't. It sounded like this Theo fella was likely to try to pull a fast one though, so if Stiles wanted him to be there, he was going to be there.
He was a little surprised to see a girl with Stiles though, and his memory supplied that the girl's name was Malia. She and Stiles were from the same world, so maybe it was for the best. Still, he caught the tail end of their conversation and frowned. She talked very casually about killing people, and that was a little disconcerting.
"Hey guys," Steve greeted from behind them. "Hi Malia. I don't think we've met yet. I'm Steve." He nodded at Stiles before scanning the pizza place for any sign of Julian. He smiled reassuringly when he caught sight of the fella in question.