-Nia is naked in the Anti-Spiral analysis/torture sequence. Inappropiate parts are covered by hair and Anti-Spiral's arm, though.
-In the middle of the Tengen Toppa battle, Anti-Spiral reveals to Simon that Nia will die if he is defeated. When Simon loses his fighting spirit, Anti-Spiral tears Tengen Toppa apart.
-Nia then summons her own Tengen Toppa mecha, Solvernia, to save Simon's life and fight against the Anti-Spiral.
-Nia's will to keep fighting and her words about how even if she can't win against "her destiny" she will keep fighting against it because that is the right thing to do inspires everyone else to keep fighting and they all summon their own Tengen Toppa mecha.
-They all get an action sequence against Gran Zeboma.
-When Lord Genome absorbs the Big Bang Storm and gives it to the Team Dai-Gurren, they use this energy to unite all the Tengen Toppa into Super Tengen Toppa, the blue giant in the OP.
-Anti-Spiral becomes a giant of energy, too. And Anti-Spiral and Super Tengen Toppa clash drills.