In the comics, what is the true identity of Black Noir?

In the comics, Black Noir’s true identity is a clone of Homelander.

Vought-American created Noir as a contingency weapon: an improved genetic duplicate designed to kill Homelander if he ever became uncontrollable. Because he possesses Homelander’s powers, Noir is one of the few beings capable of matching or surpassing him physically.

The secret is revealed near the climax of the comic series, when Noir unmasks himself and explains his purpose. His isolation and frustration over never receiving the order to replace Homelander eventually drive him insane. He impersonates Homelander while committing atrocities, hoping to make the company authorize his mission.

This is a major comic-to-TV difference. In the television adaptation, the original Black Noir is Earving, a brain-damaged Supe who is not Homelander’s clone. The show’s version of the Homelander-like atrocities is therefore deliberately different from the comic reveal.