Dio, whose full name is Dionys Diafygi ("Diafygi" is the only name used for an imp and means "escape"). He's a chubby imp who was named a water imp because water is why he's chubby and water is why his belly is cyan. He is pretty gluttonous and eating is his favorite thing to do (second place is sleeping). His favorite substance is water, ofc. He can also camouflage into every color except cyan.
Fun Fact: I came up with the first sketch of Dio before coming up with the idea of impisonas. In fact, the inspiration for impisonas WAS Dio! Another Fun Fact: he was WAAAY chubbier in the early sketches, but his "morbid obesity" was cut down here because Scratch.