Which Deep Cut member uses the alias Ian BGM?

Big Man is the Deep Cut member who uses the alias Ian BGM.

The alias first appeared through “Liquid Sunshine,” a collaboration involving the Squid Sisters. Big Man’s participation was presented as a secret, helping create the mystery around the unidentified “Ian BGM.” The name is also a playful reference to background music, fitting Big Man’s role as Deep Cut’s primary songwriter and musical contributor.

Big Man is the trio’s manta-ray member, alongside Shiver and Frye. The three host Anarchy Splatcast in Splatsville and perform together during Splatfests. Unlike Pearl, who belongs to the earlier duo Off the Hook, Big Man is part of the newer Deep Cut lineup.

A later Nintendo interview made the identity explicit when Callie referred to “Squid Sisters feat. Ian BGM” and directly addressed Big Man. Thus, Ian BGM is not a separate idol or a fourth member: it is Big Man’s musical alias.