A Guide to Appraising Heroic Spirits in the Omniverse

(A crossover supernatural-revival story. All the female Heroic Spirits will join the harem, as will female characters who aren't Heroic Spirits. In essence, this is a Lostbelt where the protagonist is every character's first partner, before their canon pairing.) After clearing FGO, Fujimaru Ritsuka transmigrated to Japan for the second time and inherited a shrine. He originally planned to get by like that, capturing female yokai and female shikigami as pets, dating a few girlfriends with distinctive personalities, and occasionally showing off in public to satisfy his vanity. Then one day, a purple-haired, mischievous AI arrived at his side with a Summoning Foundation System, throwing his retirement plans into disarray. Looking at the familiar companions in his memories, he sets out to help them escape a world where noninterference means tragedy, but intervention only makes things more tragic. By spreading the tales of the Heroic Spirits' great deeds, he can complete the System's commissions. So let's summon and strengthen more Heroic Spirits! But why are most of the ones who show up female, and why do I have to provide magical energy? Wait, I really don't have a drop left. Let me rest for a bit!