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, and the only known adult Inkling. He acts as a guide for the protagonist, issuing them the Hero Suit and title of Agent 3 in Octo Valley. He is also the grandfather of Callie and Marie.

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 Ammoses Shellendorf, 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. It takes a considerable amount of ink to completely cover him, though, suggesting that he may be more resilient than the average Inkling, despite his age and frail appearance.
 * His cane is one of many Bamboozlers used by Inkling soldiers in the Great Turf War. However, he has never been seen to use it for its original purpose, only as a cane.
 * On the corner of his shack, Cap'n Cuttlefish has taped up two small photographs of his grandchildren, one of Callie and one of Marie.
 * During the initial tour of Inkopolis upon starting the game for the first time, he is referred to as a "creepy old dude".
 * The Legendary Cap is modeled after Cap'n Cuttlefish's signature hat.