There are at least 2 bands called Mastery:

1. A Canadian thrash metal band
2. An American black metal band

1. Formed in 2001, Mastery (Canada) is an old school Thrash Metal band from Toronto, Canada. They could not find a good vocalist so they decided to play instrumental on their debut EP, Lethal Legacy, released in 2005. In November 2009, the band announced that vocalist Billy Milano (S.O.D., M.O.D.) had joined the band.

Current line-up:
Billy Milano - Vocals
Markus Armellini - Guitar
Morgan Rider - Bass
Kerry Saxena - Drums

Former/past members:
Maxell Black - Vocals (Penetrator, Krakatoa)
Kevan Roy - Drums (CayM)
Jeff Dormer - Guitar
Anthony Ristovski - Bass

2. Mastery is a one man Black Metal project from San Francisco, CA formed in 2005 Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.