Gris (グリス) is a whale with an obsession for Idate. He has yet to make an official debut in any series.
Gris has white skin, long, slate gray hair, and dark gray eyes. He wears a black suit, white dress shirt, and a dark gray tie, as well as black gloves and black dress shoes. He also has a whale's tail, signifying his species.
He has been said to be quite a confident person, not caring if Idate likes a girl, because he "never doubts for a second that Idate will become his in the end." He also appears to be the obsessive type, as indicated by his behavior towards Idate.
Not much is known about him, other than his love-fueled obsession with Idate, to the point where Gris proposes to him "on a regular basis."
Up to this day, Gris has only appeared in some of Deep-Sea Prisoner's illustrations.
Gris has unreciprocated romantic/sexual feelings for Idate, who feels uncomfortable by his presence and his overly-friendly behavior. They show up together in Sunahama 2017 11 28 on a date with a not-so-happy Idate and are shown a second time possibly proposing to him, much to Idate's discomfort. They are said to have a sexual relationship "somehow or other." It's also been said that Gris would never force Idate into anything - that he would be extremely gentle, but also extremely.... 
Not much is known about their relationship, but it has been stated that Gris knows about Nagi and has even met her many times. 
- The Japanese name of Gris (グリス) can mean "Grease" (although it is a more uncommon spelling, so it may not be related); meanwhile, the romaji reading, "Gris," in Spanish and French, means gray. This also means that Gris' name comes from Ambergris, a gray/black substance produced by the digestive system of sperm whales, with Gris being one.
- In Deep-sea Prisoner's third livestream, she said that he uses "ore" to refer to himself, confirming that he's most likely male. 
- DSP said that even without high-heeled shoes, Gris is taller than Idate and can thus kabedon him. 
- DSP has revealed that Gris is quite the proficient singer. 
Deep-Sea Prisoner Banners
- "Hellooo~" (To Idate)