Cap'n Cuttlefish is the host of the single-player campaign. He is an old Inkling that guides the player during Hero Mode.
He battled in the "Great Turf Wars of Legend" between the Inklings and the Octarians. He also keeps vigil over Octo Valley, watching for any fishy events that may occur.
He appears in Splatoon 2's Octo Expansion mode, where he supports Agent 8 as they attempt to make it to Inkopolis.
He also appears as a Master Spirit in Super Smash Bros. Ultimate. He runs one of the dojos in the game.