Deep Cut helps fight Mr. Grizz near the end of Splatoon 3’s campaign.
Shiver, Frye, and Big Man initially act as minor antagonists in Return of the Mammalians. They compete with Agent 3 and the New Squidbeak Splatoon for treasure in Alterna, but their motives are less malicious than they first appear: the trio’s bandit work is intended to benefit people in the Splatlands.
After the conflict over the treasure is resolved, Deep Cut changes sides. Mr. Grizz escapes aboard a rocket as the campaign’s main antagonist, forcing the heroes into a final pursuit. Deep Cut contributes its distinctive abilities: Frye directs her eels, Shiver provides Master Mega as transport, and Big Man supplies equipment for the journey.
The trio also joins the Squid Sisters in supporting Agent 3 during the climactic confrontation. Commander Tartar belongs to Splatoon 2’s Octo Expansion, while DJ Octavio is a recurring antagonist and temporary ally in Splatoon 3. Agent 8 is a protagonist, not the campaign villain.