Samir stared at the blond sorcerer that he and Caelus had tied up and blindfolded in some abandoned house in one of the empty human cities on the border. They couldn't bring him back to the Red Moon, as the damned council was likely spying on his every move.
When Caelus asked to bring Aero to a meeting place for the furthering of their plans, Samir and Rasne agreed that Aero would have to have his vision impaired. Samir's voice was completely unfamiliar to the wizard, so it was incredibly unlikely that he recognize him from speech alone.
Under normal circumstances, Aero would be able to recognize the Prince's vampiric aura, but he was still recovering from his wound. That and, of course, Samir's boundless knowledge and power that allowed him to hide his energy from most other living creatures.