Excuse Me, Have You Refined the Magical Girl Today?

In the modern future, people have successively excavated the remains of ancient human refuges. An ancient weapon emerged from the ruins, claiming to be a magical girl, possessing various abilities that are all-powerful. But the protagonist firmly believes that it is not the so-called sanctuary of ancient humans, but the cave relics of ancient immortal cultivators. So the protagonist founded the Demon Refining Sect, capturing and refining magical girls all over the world, just to achieve his true immortal status!