Shirou
Shirou was surprised to see the spike evaporate into what seemed to be a cloud of blood, the red mist seeping around the house. However, he kept his concentration, focussing on the man who had broken into his house as the traps triggered. To Shirou's surprise, a small tendril of what seemed to be blood came from the man's fingers, swatting away the tendrils of magic from the trap as if they were nothing. Then, the man spoke up, his praise of Shirou's fighting skill making it clear that he wasn't taking this whole thing entirely seriously.
Still, it was clear that the man was a threat and, unlike him, Shirou had no intentions whatsoever of playing around. This man had broken into his house and attacked him, he clearly needed to defend himself with full power. Yet, even despite his best efforts, he could barely manage to react when the man stomped down, before charging towards him. Shirou did his best to evade but, to his surprise, the man made no attempt to attack him, instead simply rushing behind him, crashing through the wall and causing further damage to their home, something that made Shirou even less keen on this man.
Then, the man addressed him once more. Shirou ignored his bullshit excuses, not even slightly interested in bantering with his attacker, but his follow-up question left Shirou shocked and worried. The latter because of the fact that this man who, presumably, was some kind of mercenary, was searching for his wife, and the former because he had used a form of Sakura's former adoptive family's name that hadn't been in use for centuries. For a moment, Shirou considered his response, torn between wanting to know the man's intentions and not wanting to put his wife in danger but, ultimately, there was only one answer he could give.
"Sorry, I don't know anyone with that name", he said, entirely truthfully.
Not that he had any objection in principle to lying, of course, but he suspected the man knew more than he was letting on, and openly lying might offend the man's sense of "honour".