Levi hadn't minded Ren tagging along when they ran into each other in the hospital. (He would have followed Ren anyway.) The sneaking and fighting style hadn't been weird enough for Levi to say something but when Ren summons his persona the dog-eared, dog-nosed boy with the rifle and moth wings double takes. He'd seen other people do that!

Once the battle is done and its safe to say something, Levi speaks up. "That big guy...you summoned it?"