Hot on Upgrading Mecha Girls

Nora Lopez is an E-rank Mecha Girl, close to dying and marked for scrap, when Caesar Leat gets hold of her. He upgrades her to SSS-rank. She is the first Mecha Girl he has ever rebuilt, and from then on she fights for him. Caesar had been pulled into a world run by Mecha Girls and arrived with F-rank talent, which had everyone writing him off. His own Mecha Girl betrayed him, and his relatives were after the inheritance his parents had left. At the lowest point the Upgrade System woke up in him by accident. It can raise any Mecha Girl to SSS-rank or above. With Nora he enters the Mecha Girl Tournament, wins it and takes the inheritance back. Power on that scale gets noticed. The Mechanicus, an elite that runs things from the top while staying out of sight, has a plot under way and has worked its people into the highest levels of authority. Caesar, Nora, Stella and a few others dig out the infiltration and break the plot up. Caesar goes on upgrading his Mecha Girls one at a time and builds them into a legion.