Name: kishin asura
Species: kishin. Maybe a bit of death God
Age: around 800

Appearance: 

Abilities:

Flight: self explanatory

Regeneration: again, self explanatory. While he can regrow lost limbs and heal from nearly being cut in half, if the damage is severe enough, it could kill him

Overall difficulty in dying: asura has survived things that would kill a normal human being. Ranging from wounds that nearly split him in two, to his most notable feat of spending 800 years without food, water, or oxygen, trapped in a bag made from the skin that had been torn off of his own body, prior to having every drop of blood drained from his skinless (and still living) body. Only to emerge alive and practically unscathed.

Black blood: the substance that was injected into his body, and what revived him from his 800 year....nap... is the same thing that now flows through his veins. Not only does it provide great defense, but it is also known for making most people go crazy once it gets into their system

Madness wavelength: as a kishin, he is practically his universe's embodiment of madness. Nothing makes this clearer than his soul wavelength. An extension of his soul, and something not to be messed with. It can make people go insane, and make illusions.

Vajra: before he went insane and got sealed away in the most brutal way possible, he had a partner named vajra. Spoiler alert, vajra got eaten. Now asura can partially regurgitate his old pal and use him to fire lasers.
It's a long story.

Witch's soul: after consuming the soul of the spider witch arachne, asura turned into a giant monster. Despite not being a giant monster anymore, he could yet draw power from this

Skin scarves: those scarves aren't just for show. Asura is able to utilize them as extra arms. Also, they are made from his own skin....yeah...

Hand-to-hand: he's good at hand to hand combat.

Shield: a simple red energy shield he can materialise at a moment's notice. While it is pretty durable, a strong enough attack will break through it

Weaknesses:

Madness: he is one can short of a six pack to say the least

Fear: asura was (and still is) afraid of practically everything, even before going insane

Bio: (long story): in an attempt of better himself, the mighty lord death cast away his fear and whether or not it was intended, asura was born. As a being of immense power equal to lord death himself, asura worked under his "father" and hunted witches. However, as he was born from fear, asura was afraid of everything. In an attempt to ease those fears, lord death paired him up with a death weapon. A being with the ability to transform into a weapon . This weapon form being a golden spike also called a vajra (the more you know). What was the death weapon's name? Vajra.

Original I know.

This didn't exactly work and asura's fear persisted. Until one day he thought of an idea. Achieving ultimate power. He reasoned that in doing so, he would finally have nothing to fear.

That may have been the start of his descent into madness.

After killing a bunch of people, eating their souls, and swallowing his weapon partner, who was in weapon form, asura became a serious threat. So lord death hunted him down and sealed him away in the least PG way he could. He drained the mad god before stuffing him in a big old bag made from his own skin. Asura's skin, not lord death's. Afterwards, he anchored his soul to what would one day become death city. Spoiler alert, it was a bad idea.

Fast forward eight hundred years, everything's peachy. Until an attempt is made to free asura. Long story short, he gets free, squares off with lord death, and then flees. Lord death being unable to follow him due to the soul anchor thing.

After some time, asura secluded himself in a temple high up on a mountain, where he was found by the spider witch arachne. After nearly killing her with his skin scarves, the witch and the demon formed an alliance, and he ended up joining arachnophobia. Long story short, there was a big battle. In the midst of it, asura squared off with lord death a second time and almost killed him. After realizing his growing feelings for arachne, he flew away, went to her, removed her soul from her body, ate it, became a giant monster, and died from a punch to the face after a battle in which he survived a laser blast of certain death fired by lord death's son, death the kid.

Again, pretty original.

Some time later, asura experienced undeath, in the sense that he stopped being dead. How that happened is unknown, and perhaps it is best left that way.