My SSS-Rank Mecha Maiden

In an apocalypse of Insectoid invasion, Luke Landon awakens SSS-rank talents. He forms a pact with Campus Belle, Zoe Sullivan, who appears F-rank but is secretly a hidden SSS-rank mythic mecha. Luke Landon forms pacts with multiple SSS-rank Mecha Maidens, sweeping away Insectoids, saving Humanity.