Most Precious Blood fuses the doomy sound of metalcore with a lyrical intent strongly influenced by political hardcore acts from Crass to Fugazi, with a particular focus on veganism and animal rights issues. Most Precious Blood began in the early '90s as the Brooklyn-based hardcore band Indecision, which featured singer Tom Sheehan and guitarists Rachel Rosen and Justin Brannan. After four albums (including 1996's Most Precious Blood, named after a private Catholic high school in Brooklyn that had been the crosstown sports rivals of Brannan and Sheehan's own school), Indecision split up rancorously while on tour in 2000. Following that band's split, Rosen and Brannan drafted Sheehan (who had left Indecision in 1998) to form the more experimental and metal-edged Most Precious Blood, rounding out the original lineup with another former Indecision member, drummer Pat Flynn. Following the release of their 2001 album Nothing in Vain, Rosen (who had played bass on the album) moved back to guitar and the band added Matt Miller on bass and replaced Flynn with Sean McCann.