Leviathan Zero: Return of the Drowned Kin

Former fleet commander Rowan is framed as the "Drowned Traitor" after his family and fleet are slaughtered. Saved by Elara, he hides as a mechanic. When she is nearly killed, his mech Leviathan Zero awakens. He returns, exposes the Vane Consortium's kaiju conspiracy. His sister Mia, believed dead, is now a biological core. Rowan, Elara, and Mia achieve 100% neural sync, close the Abyss Gate, clear his name, and replace military rule with a shared alliance.