Katu is an Inuin and a living conduit of interatmospheric anomalies. He lost his arms in a battle with Omega Red and had cybernetic arms attached.
At some time, Katu fought Omega Red, and lost his both arms in the confrontation. Obtaining bionic prosthesis for his lost arms, he swore revenge on his enemy, and joined the Acolytes.
Eventually, the Acolytes allied themselves with Cable in order to stop Omega Red, and Katu saw there an opportunity. During the battle, Katu unleashed his powers in a blast that seemingly killed him and Omega Red. Both survived, with seemingly no effects.
He was among the millions of mutants who died during the Wild Sentinel attack on Genosha.
Katu was later resurrected by the Transmode Virus from Selene, along with some other Acolytes.