[Vallen Chaos Valiant]

Originally Posted by VentAileron

Spoiler for Response:

It was implied that it was a fake name by Kyon's narration (so Kyon thinks it's a fake). If he's truly Mikuru's brother (is he older or younger than Mikuru?), then his family name would be Asahina.

You are assuming Mikuru Asahina is using her real name.

If I was to run a time cop agency, I would make sure all my agents work under full aliases. It simply doesn't make sense to use birth names that might cause issues when in the Past. That is unless, of course, Mikuru is forced to use her real name because of temporal consistency. But I find that unlikely.