Skarr Bloodwrath
Skarr Bloodwrath is one Champion of Chaos introduced in the final tome of The End Times who pretty much heralded the coming fate of Khornate Warriors of Chaos being overly edgy with their names and weaponry. After all, the man himself is carrying a matching pair of axes with flails attached to their hafts.
His tribe is the Skaramor, whom were born and bred butchers obsessed with blood, skulls, and other wholesome things. Skarr himself naturally learned to kill the moment he was old enough to pick up an axe. When he grew of age, he decided to kill his own chieftain. Impressed, the big red guy decided to mark him.
This gift only revealed himself as he made a one-man siege on a Tzeentchian wizard's fortress, backstabbed by the wizard's illusions. Khorne called this a cheap shot and decided to respawn Skarr using the blood of the 999 minions he had slain. Thus is Skarr's OP gift: he has a respawn timer, like his life were some free-to-play mobile game and his currency is in pints of blood. The only real drawback to this power - if it could even be considered one - is that each respawn sees Skarr lose a little bit more of his humanity. Not like he cares; he rather enjoys all the bloodshed, and by the point he crossed paths with Archaon, he had transcended any need for sustenance. Quite frankly, the only reason he even joined the Everchosen's campaign was because Khorne thought it interesting.
Of course, the power to respawn at the Blood God's behest meant that blowing up the old world didn't mean a thing. Thus Skarr went back to the circuit of incessant murder and carnage, fading back to irrelevancy.