Ainz - Friendly Signal

They hadn’t known it was him just because he’d teleported—there was another way. Momonga could not perceive them, but all the minions in the Great Tomb of Nazarick—or rather, all the minions that belonged to Ainz Ooal Gown—gave off a wavering signal. They used this signal mainly to determine if someone was an ally or not. And the Forty-One Supreme Beings—currently just Momonga—“felt” to the minions like absolute rulers. It was such a bright signal that it could be sensed even at a distance. That was why even though he was covered in armor, there was no mistaking him. They would have known it was him instantly, even if he’d strolled in instead of teleported. And it was easy to distinguish that signal from any others.
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Volume 1, Chapter 3.1