Bile Fascination: The story does not shy away from gruesome acts of torture, dismemberment, and various forms of gore and bloodshed. This is precisely the reason people come to read it.
Complete Monster: Princess Alesia is the one responsible for summoning Ueki Kaito to her world. In the prologue, after having him save their world, Alesia reveals her true colors, spending a year hunting him down like an animal for her own sick pleasure before succeeding at stabbing him to death with her comrades. Upon Kaito's return, he learns Alesia sacrificed 200 beastmen slaves to summon him, while also condemning 5 of his relatives (and 200 of his classmates and teachers) to horrific deaths. Sickeningly racist and xenophobic, Alesia orders bloody purges of anything with less than 100 percent human blood, even having a village butchered so the souls can be offered to a powerful demon for her benefit. Alesia promotes brutal slavery throughout the land, even on the majority of her own citizens, and when she confronts Kaito, gleefully states she'd happily have him impregnate some beast-man sex-slaves and kill the newborn children right before him.
Magnificent Bastard: The brilliant, charming Ueki Kaito ruthlessly takes any means necessary to avenge himself against those who betrayed him after he saved their world. Recruiting a young slave girl, Kaito viciously helps her poison both the slaver and the other slaves, transforming them into goblins and then killing them. Later allowing the Royal Capital to be ravaged by beasts, Kaito uses the destruction of an outer wall to escape. Pained by guilt after an innocent girl is caught in the debris, Kaito henceforth swears to avoid harming the innocent in his quest for vengeance.
Whole Plot Reference: Uses the same general plotline as The Rising of the Shield Hero (betrayed and shunned by the people who needed him, swears revenge and to be less gullible, battles the evil princess who victimized him and the evil god/goddess she is tied to), except this time the hero reallywent off the deep end, turned sadist, and brought his party with him.