A demonic elf who uses the magic of the Legion against them. A havoc demon hunter is an aggressive melee damage dealer with high mobility. They have adopted traits of demons and use their own power against them.The main thing that makes Demon Hunters truly special is Metamorphosis.
An extremely useful tool for overall optimization
WoWhead Havoc guide
http://www.wowhead.com/havoc-demon-hunter-guide
Icy Veins Havoc guide
https://www.icy-veins.com/wow/havoc-demon-hunter-pve-dps-guide
Noxxic Havoc guide