Warning! Some of these are dark themes. Really dark. Like, DOOM dark.

He was a simple farm boy, living in his village with his family and friends. His family was him, his father, mother, and sister.

But that all changed when heaven and hell went to war. His village was one of those that were right in the middle.

Demons invaded the village and killed everyone, except him. He was found by the succubus queen who had a 'thing' for young boys. So… she raped him while making him watch as demons killed his family.

On that day, whatever innocence he had were gone. For three years the succubus queen kept him as her personal slave. She thought that she had broken him. But she was wrong.

One day, when the queen turned her back to him, he picked a sword from the walls of her castle and cut her head off.

He then continued that path of blood killing every demon in the succubus queen's castle, sparing no one.

He then made a declaration: If demons didn't show him any mercy, then why should he show them any?

Driven by rage and hatred, he started a massacre, killing all those who crossed his path in hell while gathering an arsenal of demonic weapons.

On one of his killing sprees, he discovered an ancient demon temple which held an orb of incredible and ancient power, that power was called the Crimson Nova energy.

The Crimson Nova energy bonded with him. Any living being would have been killed, but through sheer will and thirst for revenge, not only did he survive, but he was granted incredible power.

With his new power, demonic armor and weapons, he traveled through the fiery depths of hell killing all who stood in his way.

The demons of the underworld gave him a name. A name inspired by what he does and leaves behind him… Genocide.

Genocide walked through the underworld, killing everything that stood in his path in the most horrific way possible. None survived his cruelty.

One day, he encountered one of the seven deadly sins, Wrath, who challenged him into battle.

The battle was fierce, both of them used anger to get stronger. But, Genocide had more than anger, he had hatred.

Putting both emotions into his fighting, Genocide managed to kill the deadly sin of Wrath.

As proof of his victory, Genocide took Wrath's sword, Rampage, and his gauntlet, Crusher. That was the day he was crowned the unofficial Sin of Wrath.

The Olympic God of the underworld, Hades, wanted to stop this massacre in his domain. But it did not end well.

Genocide had an advantage thanks to the Crimson Nova energy. He defeated Hades and would have killed him if it was not for Zeus coming in and escaping with his fellow God.

The Unofficial Sin of Wrath decided that it was time to kill the demons from their head… Satan and the Demon Lords.

There were four demon Lords working for Satan. Lucifer, Beelzebub, Asmodeus, and Leviathan.

Genocide fought the Demon Lords, each one in their own domain. He killed Leviathan in its frozen sea. He killed Asmodeus in his battle arena. He killed Beelzebub in his rotten city. And he killed Lucifer in his flying castle.

The only one left was Satan himself, and Genocide showed no fear in facing the demon king.

The battle was destructive and long. Anyone who was close by ended up being caught in the crossfire and killed. After exactly three days of non-stop battle, Genocide was finally able to defeat Satan and stab Rampage through his chest.

With his dying breath, the demon king tried one last thing to kill Genocide. He opened a black hole.

Normally, Genocide wouldn't have a problem avoiding such a thing, but his battle has worn him out and he was sucked into the unknown.

Facts:

#1: the Crimson Nova energy is one of the oldest and most powerful energies in existence. The only thing that can withstand it and heal from it is an energy or a being that existed since time itself.

#2: Genocide was already strong enough to rip demons apart with his bare hands before he got the Crimson Nova energy, and he became stronger after gaining it.

#3: Despite his usually brutal ways, Genocide still upholds some honor and shows respect to those who earned it. (Example: when Asmodeus, the most honorable demon Lord, challenged Genocide to a fair fight with just swords, he accepted and won fair and square.)

#4: Genocide is feared by most the supernatural world. Originally, they were only worried, but when he defeated Hades, fear began to rise.

#5: Rampage, formerly Wrath's sword, now belonging to Genocide, is one of the most powerful swords in existence, and can only be outmatched by godly weapons.

#6: Genocide had many chances to leave the underworld, but he took none of them. He decided to stay and finish his sworn mission of revenge.

#7: While appearing like someone who would only use brute force, Genocide actually knows the advantages of having a plan.

#8: Genocide's weapons and armor are a mixture of technology and demonic magic.

Personality:

Genocide personality became rather cold while spending years in hell. He does have a soft side that he only shows to people he trusts and children. He hates heaven and hell equally because of what hell did to his family and friends, and heaven for not doing anything about it.

Looks and Gear:

Genocide doesn't usually if ever takes off his armor. (In other words, use your imagination to think of what he really looks like and his age. And If one you thinks about using Naruto, you are dead to me.)

His armor, except his right arm, is completely white since it's made from demon bones. The joints glow and eyes glow red from the Crimson Nova energy. His helmet looks like a demon skull with two goat horns on the sides. He has a white armor with spikes on his shoulders and his left arm's knuckles are covered in spikes. His right hand, however, has Wrath's gauntlet. It is black, somewhat bulky, and has claws for fingers. He wears black pants with bone armor around the knees. His boots are covered in bones making them look like claws.

His sword, Rampage, is a pitch black blade with a red saw-like edge.

His main firearm is a white demonic shotgun that transforms into a rifle. He has a set of different demonic weapons, but his most powerful is the Cyclops Blaster.

The Cyclops Blaster is a giant laser gun. It is powered by an eye of a cyclops that Genocide had killed. It looks like a tube and its laser can destroy almost anything.

Possible universes:

Marvel

DC (Personally, I want this one so I can see Trigon or Injustice Superman has their ass kicked.)

High School Dxd (This is the most likely one.)