Inside the Cave of Obscenity - Vol 9 Chapter 1: The Hero's Return

At the Tristain Magic Academy, her classmates call bumbling witch-in-training Louise Francoise le Blanc de la Valliere “Louise the Zero.” During an important coming-of-age ritual, when each student must summon their own witch’s familiar, Louise confirms her classmates’ opinion by accidentally conjuring up a normal teenage boy from Japan. Whether the two of them like it or not, the laws of magic bind them as master and servant forever! A hilarious novel with romance interwined.

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates

Once an imperial princess, now reborn among the lowest of s*aves of the nobility.

When gods gather, lightning will strike and the earth will move. Immortals! Which of the numerous way to immortality should one follow? Immortals are hard to seek, but why should immortals hide? Heaven has no mercy, but humans have emotions, and these emotions hinder the road to longevity!