Ranhart

Ranhart, the Skeletal Phantom
Ranhart appears as human skeleton with black bones covered in cloud of dark purple smoke and flames which is in fact his soul. His bones slowly burn away and he needs to steal calcium from living humans to rebuild his body, which results in painful deaths of his victims. When he can't pierce through skin so he either goes for the teeth first (as it's the only part of human skeleton not covered by flesh) or tries to cause open wound deep enough so he can reach bones. Ranhart is only able to see the world around with his soul. Sunlight is lethal for him, as it dissolves soul with no body to cover it.

After 2000 years in The Void his mind is gone. His soul if full of hatred towards... basically everyone. He wants to find people from Nekaru who left him there but doesn't realize they all are long dead and attacks anyone on his way believing that finally he will find them.

Story
Somewhere between physical reality and eteric dreams is a place older than Reality itself. Endless cave at the bottom of infinitely deep sea, place where time doesn't exist, place which cannot be comprehended by nor mortals nor eternals, place known as The Void. Over 2000 years ago, in their Golden Ages humanity discovered how to open a gateway to this dark dimension. They couldn't see, feel nor describe true nature of this anomaly, yet they found use for it and through years countless Eternal Ones who humanity saw as unnecessary complication were trapped there. Some escaped with help from mortals and some were lost forever in infinite darkness. After The Age of Death when humanity resumed their cooperation with Eternal Ones existence of The Void and it's dark history was forgotten by most, and new law considers opening Void gates as war crime.

Everyone forgot about tragedy of Ranhart known as Headsman of Immortals. 2000 years ago humans harshly judged both gods and demons for any misdeed, and most of them ended up forever trapped in The Void. Like headsman who strikes convict with axe Ranhart was the one who pushed screaming eternals into infinite nothingness, until the day when god he was about to banish pulled his executioner with him. Ranhart screamed for help but nobody could reach him before he fell down into The Void. He was alone in endless black pit and nobody would ever try to rescue him.

Unable to die he slowly lost his sanity, and his mind was filled by hatred for those who left him there. After eternity of pointless wandering in endless caves Void gateway opened by secret society worshiping all trapped there eternals let him escape, but the thing that crossed the gate can hardly be considered human anymore. His flesh burned to dust and his bones cracked but after all he suffered Ranhart just... refused to die. Power of his hatred was stronger than any magic Greavesoyl ever saw, emotion so strong that it denied laws of the universe, hatred so pure and infinite that it could deny death itself. Ranhart was alive but his old body was gone. He became a living skeleton and his own soul was slowly burning his bones away and the only way to keep his body was to constantly rebuild his new form with fresh calcium.

Calcium of anyone who crossed his way.

In-game
Ultimate duelist, the Skeletal Phantom was designed to never lose 1v1 melee fight. His life steal allows him to fight longer than most fighters while his unique disarm makes it even harder to fight back. Even when things go wrong this spooky scary skeleton can just turn into cloud of smoke and escape.

Trivia

 * "Spooky scary skeleton" was at first designed as halloween joke but he actually made it into the game.
 * Ranhart doesn't know how long he was trapped in The Void and is still seeking for his old colleagues, not realizing they are all long dead.