Bill Kelliher

William Breen Kelliher (born March 23, 1971) is an American musician, best known as the rhythm guitarist of heavy metal band Mastodon, and being the only band member who doesn't share the lead vocal duty.
Kelliher is an Irish citizen, he holds dual citizenship with the United States and Ireland. His father is an Irish immigrant who, in his teenage years, moved to the U.S. from Killorglin, County Kerry, Ireland.
Kelliher performs a number of different roles within Mastodon. These include backing vocals during live performances, complex guitar parts and occasional lead guitar. He is also running the samples and ambiance in between and during songs. He shares guitar duties with Brent Hinds, playing mainly complex rhythm parts, although Kelliher occasionally plays solos, such as on "Sleeping Giant", and harmonized dual leads with Hinds, such as on "Black Tongue".[citation needed]