Gallhammer (/ˈɡælhæmər/) were a Japanese extreme metal group that drew on blackened crust, black metal, doom metal and crust punk. They formed in Tokyo in 2003 and released three studio albums. The current group lineup is Vivian Slaughter (vocals, bass guitar) and Risa Reaper (vocals, drums); the original lineup included Mika Penetrator (vocals, guitar).