Black Mask (1996) Jet Li

Simon (Jet Li) appears to be a mild-mannered librarian, but he's actually a genetically enhanced solider who feels no pain. His team of super-soldiers, code-named Squad 701, was disbanded after some of them had psychotic episodes and exhibited mental instability. Simon thinks his fighting days are behind him, but when members of the squad, led by his ex-commander, Hung (Patrick Lung), start murdering drug dealers, Simon dons a black mask and searches the streets for his former comrades.