FGO: Today, We Too Must Be Good Masters

This is the story of Alter Murasaki Shikibu, a version of Miss Murasaki Shikibu from a parallel world. Instead of becoming the final boss+, Murasaki Shikibu is lucky enough to become Professor El-Melloi's most outstanding student in a parallel timeline, only to accidentally become humanity's last Master. Young Murasaki Shikibu wonders, "What the heck? Is humanity's future really going to end up in the hands of someone like me, who might become a powerful antisocial boss?!" But the male Heroic Spirits in Chaldea, who secretly adore her, all say, "You're the best Master I've ever met, young lady." So the clueless young Murasaki Shikibu, showered with praise, thinks, "Then I have to work even harder!" It isn't until she summons versions of herself with all kinds of Heroic Spirit classes that she realizes things are nowhere near as simple as she imagined.