Metallica was recognized has being one of the founder of the gender. Dave Mustaine, Megadeth's front man, singer and guitarist was the first lead guitarist of Metallica back in 1982. When he got kick-out of the band in 1982 and replaced by Kirk Hammett (from Exodus) for alcohol and drug abuse, Dave started this new band named Megadeth.
First Metallica Line-up - James Hetfield, Ron McGovney, Lars Ulrich and Dave Mustaine - 1982
Megadeth "Killing" Line-Up - Dave Mustaine, Gar Samueson, David Ellefson, Chris Polland1983
Their first album "Killing is My Business...and Business is good" with Metallica's first album "Kill 'Em All" are considered as one of the key album of this era. As it is one of my favourite album of the era, I have a few pressings, including an extremely rare First Press test pressing.
Megadeth - Killing Is My Business... - 1985 - US - Combat - Test Pressing
Megadeth - Killing Is My Business... - 1985 - US - Combat - First Press
Megadeth - Killing is my Business... - 1985 - Canada - Banzai Records
Megadeth - Killing is my business... - 1985 - Music For Nations - UK