After forming a contract with the Demon Queen Erinyes and gaining the most powerful mana of any mage in history, the future is looking bright for Eugene and Sumire, the reincarnator from another world. In order to turn Sumire back into a human and return her to her original world, the pair are aiming for the 500th Level of Babel. With the help of the Holy Swordswoman Sara—who still has feelings for Eugene, her former partner—they make short work of Babel’s numerous floors. But a nasty surprise is waiting for them at the Hundredth Level. The Discipline Beast they must defeat is none other than the Demon Queen Erinyes herself!
While at its core it is an entertaining enough story, fairly typical for its genre at least as far as tropes and characters go, it comes with the same flaws as well. For me the harem shenanigans drags it down a bit, not that there is a harem (while not a fan, I don't hate it either), but that the girls are constantly fighting/arguing with each other is what I dislike. The way how the demon queen treats the MC is also a bit off putting even if it is with reversed gender roles. For now I am enjoying it well enough, but it does require at the very least some tolerance for certain (anime) tropes and depending on how things develop it might quickly turn into a story that is not for me.