The way a lazy metalhead named dave mustaine spelt death because he was unwilling to conform to current spelling specifications and trying to prove himself a badass. Though this did not work, and we know he is very girly, we excuse him because he does have the power to shred guitar. Also, it did catch on in his bands name megadeth. Now deth can be used to refer to music that is incrediby heavy and full of raging wild solos with no particular structure and are just a display of how fast one can play their guitar and how far up the neck they can do it. This is all backed by thick, crunchy, fast, palm-muted rhythms, loud unnintellegible singing/growling, and double-bass so fast and loud you will puke blood and evacutate your body of all fluids and eventually your head will explode. This is known to happen while listening to megadeth, and it is also common for these effects to happen while listening to the band dethklok.
"Did you hear about that guy who died?"
"Yeah, his head exploded because his music was too deth."