Gearmaster Mechazod is a powerful Mechagnome who was rebuilt from titan parts found near Fizzcrank Airstrip and has now gone mad. He (or, perhaps more accurately, "it") wants to rid the world of "the Curse of Flesh" and has created an army of lesser Mechagnomes to aid him in his quest. He currently resides in the Borean Tundra.
Because of his deranged crusade against organic life, both Greatmother Taiga of the Horde and Fizzcrank Fullthrottle of the Alliance have placed a bounty on his head.
This has directly aided the Old Gods who inflicted the Curse Of Flesh on the species of Azeroth eons before to make them easier to assimilate and enslave.