William Petenshy

These two men were appearing to have an argument outside of Sōseki Natsume's residence during Ryūnosuke Naruhodō's investigation of Viridian Green's attempted murder.

They are described in the art book as Mysterious Man A (the one in pink) and Mysterious Man B (the one in yellow).

Mysterious Man A wears flashy clothing that look remarkably out of place and acts very antagonistic towards Mysterious Man B and has a very high sense of self, as well as calling everyone Horatio. He lives in the same building as Natsume.

Mysterious Man B wears bright yellow, hornet-like clothing. He is rather irritable towards Mysterious Man A and Naruhodō.