1. One of the most bad-ass demon slayers/killers to ever be brought forth into fucking existence.
2. Usually refers to your death multiplied by a very large number. If someone uses this phrase in a sentence, it means they are located within Hell in its deepest, darkest, and hottest pit, and still sensed you shit your pants.
Ok, Kyle ; (... I see how you want to go at it. Man, fuck super saiyan, prepare to face the wrath of the Doom Slayer, fool...
In the first age, in the first battle, when the shadows first lengthened, one stood. Burned by the embers of Armageddon, his soul blistered by the fires of Hell and tainted beyond ascension, he chose the path of perpetual torment. In his ravenous hatred he found no peace; and with boiling blood he scoured the Umbral Plains seeking vengeance against the dark lords who had wronged him. He wore the crown of the Night Sentinels, and those that tasted the bite of his sword named him... the Doom Slayer.