Megadeth is an American heavy metal band formed in Los Angeles in 1983 by vocalist/guitarist Dave Mustaine and bassist David Ellefson. Known for their technically complex guitar work and musicianship, Megadeth is one of the "big four" of American thrash metal along with Metallica, Anthrax, and Slayer, responsible for the genre's development and popularization. Their music features complex arrangements and fast rhythm sections, and lyrical themes of death, war, politics, personal relationships, and religion.