old man (guin guin)

An OC created by Guin Guin whomst appeared originally in the artist's Kancolle-related works, but has since become the center of their ongoing Arknights story as a stand-in for their world's doctor.

His real name was revealed to be Aldrino in his debut story, though it is used sparingly when referring to him (same with the shortening of Ald).