Gurren Lagann (2007)

S1E10 Who Is This Bro?

Nia's true identity comes to light as she wields her power to eliminate Adiane, another of the Four Divine Generals. The Great Gurren Brigade grows wary of Nia and her hidden motives, yet her attention remains fixed on a despondent Simon. Later, with Lordgenome's approval, Adiane makes her return, determined to wipe them all out.