Haruhiko and the Frogman

"You're very much alone."

"We'll always be at your side, Tamamori-san! Always! Forever!"

Characters from Tamamori's novel, "The Mysterious Man in the Basement." While they seem to be nothing more than a hallucination at first, they go around drinking tea and playing Go and act as they please, as if they were real.

While Tamamori is hard on them at first, they slowly grow to become his emotional support...?