Deep Cut are the idols featured in Splatoon 3, consisting of Shiver, Big Man and Frye! This is the only idol group heavily featured in a game that is a trio, rather than a duo. As Splatsville's resident idols, Deep Cut hosts the Anarchy Splatcast and Splatfest events, with one of the three representing one side of the Splatfest. When they are not preforming their duties as the local idols, the three of them secretly work as bandits to steal treasure, sell it, and split the money amongst the poor in Splatsville (keeping a small amount for themselves).
Shiver, Big Man and Frye were not initially close in childhood. All three of them are descendants of families that have officiated Splatsville's traditional festivals (the predecessor to the Splatfest) for generations. As such, the members only greeted each other in passing when their families got together. They only started to become closer in middle school. Frye and Shiver bonded over music, and Big Man joined later on.
In Splatoon 3's story mode, Deep Cut takes an antagonistic role, saying that Alterna is theirs to loot. The three are fought as bosses at different Alterna sites, and, once they are defeated, they drop a piece of 'treasure'. Once all of their treasure is collected, the New Squidbeak Splatoon create a tool with it, so that they can reach the rocket. Deep Cut appears shortly after, trying to reclaim the treasure they lost, but Marie gives it back without a fight, much to the trio's shock. They're emotionally moved by the New Squidbeak Splatoon's generosity, and feel guilty for their attempts to splat Neo Agent 3, so, they ask Marie to be their boss, who hesitantly agrees.
After Neo Agent 3 climbs the rocket to fight their enemy, Shiver and Frye use their powers to help launch them into space. Big Man, meanwhile, gives Neo Agent 3 headphones designed for space. During Neo Agent 3's final battle against Mr. Grizz, Deep Cut collaborates with the Squid Sisters to sing Calamari Inkantation 3MIX to hype Neo Agent 3 up.