If you're looking for manga similar to 3x3 Eyes: Seima Densetsu, you might like these titles.
On a remote island, a skilled swordsman who honed his craft on the local population attempts to atone for his sins and lift a curse by hunting and killing demons.
Across the world, malevolent beings known as il inhabit enchanting objects to entice curious humans toward them, and in doing so they devour the heart and freely use their victims’ bodies as puppets. To combat the threat that the il pose, hunters called Syste Behards roam the land fighting their prey to keep innocent civilians safe. One such hunter is March, who has an incredible ability capable of subduing, exorcising, and defeating ils. But with a dark power sleeping inside that threatens to overwhelm the young Syste Berhard at the first sign of falling in love, can March continue to fight the il and still remain human?
The city of Hole is a desolate town where magic users go to test their powers by disfiguring or killing its people. After being cursed by a sorceror, Kaiman was left with the body of a man and the head of a lizard. Determined to break the spell over him, Kaiman works with his companion, Nikaido, to search for the one who made him this way. Unfortunately, with no memory as to his assailant’s identity there’s only one way for him to locate them: he must bite the head of any magic user he meets so that the man hidden inside him can determine if they are the culprit. As he bites, slashes and kills his way through the cruel magic users, will Kaiman be able to find out who the man in his mouth is, where the one he hunts is hiding and return to normal, while keeping the revengeful magic users at bay?
The new demon king, Vermot the 13th, is bored of his life in the demon kingdom, so he decides to take over the human world. He heads there with his sword and his pretty maid, Sara. With his powers and abilities, he is easily able to take over the first kingdom he targets, reduce the surviving princess to his pet, and slaughter any righteous heroes that come his way. He loves how he can take whatever he wants with his own power in this new life, rather than it already having been given to him (as in the demon world). He's not planning to stop his conquest anytime soon...
There's a legendary killer stalking the street whose name comes from a monster of our nightmares, one that emerges from the shadows to feast on the evil-doers. And tonight, he has his sights on a gangster who has a trick up his sleeves too.
The Arnold Academy of Magic is a school for the elite...and Ray White is just your ordinary guy. In fact, he doesn't seem particularly skilled with magic at all, and is a bit of a klutz. Which is why he has nothing to do with the rumor that one of the great magicians, the Iceblade Sorcerer, is a member of the incoming class...right?
Muol Reed, aka criminal no. 5722, has been condemned to life in jail for murdering his superior officer. But for some reason, instead of being hauled off to rot in prison, the ex-soldier is taken to an enormous graveyard guarded by a haggard old man and a slavering dog, and instructed to start digging. Muol assumes the enormous holes he's digging are mass graves for fallen soldiers, but that couldn’t be farther from the truth. For when a group of mysterious masked men arrive at the graveyard one day, the digger learns the truth about humanity's greatest enemy: the Dark.