Cuttlefish

"This unreasonably attractive gentleman goes by the name of Cap'n Cuttlefish. He’s a decorated hero who fought in the Great Turf Wars of legend between the Inklings and Octarians. He now keeps solemn vigil over Octo Valley, watching for any fishy behavior. Though his clothes may be tattered, his heart is pure and nothing escapes his razor-sharp gaze. He also TOTALLY didn’t write this post."

- Live from the Squid Research Lab

Cap'n Cuttlefish (Japanese: アタリメ司令 Commander Atarime) is a main character in Splatoon. He is an elderly Inkling. He acts as a guide for the protagonist, issuing them the Hero Suit and title of Agent 3 in Octo Valley.

History
Prior to the ultimate end of the Great Turf War, Cap'n Cuttlefish served as leader of a division called the Squidbeak Splatoon alongside Sheldon's great grandfather, Judd and two unidentified Inkling soldiers.

Personality and traits
Cap'n Cuttlefish is a decorated hero who fought in the Great Turf Wars of legend between the Inklings and Octarians. He now keeps solemn vigil over Octo Valley, watching for any fishy behavior. Though his clothes may be tattered, his heart is pure and nothing escapes his razor-sharp gaze.

Cap'n Cuttlefish seems to have a liking to crab cakes/biscuits as pointed out by Agents 1 and 2 which often distracts him and leads to trouble without his attention, unaware that this gave DJ Octavio the chance to escape from his snow globe prison.

Trivia

 * In the main hub of Octo Valley, the player can ink Cap'n Cuttlefish; he will eventually shake off the ink, however.