Complex sentence: However, Nene is later revealed to be a figurehead for Midnight's true leader AxeKnightmon, who blackmailed her into aiding him; after he attempts to dispose of her once she outlived her usefulness, Nene joins the Fusion Fighters.
Split into simpler sentences: However, Nene is later revealed to be a figurehead for Midnight's true leader AxeKnightmon, who blackmailed her into aiding him. But when he attempts to dispose of her once she outlived her usefulness, Nene joins the Fusion Fighters.