Reverorum Ib Malacht
In their early years, Reverorum Ib Malacht were part of the anti-cosmic Black Metal community in Sweden. However, in 2009 Lundin (formerly also known from Dödfödd, Ofermod or Emit) and Mikael converted to Catholicism (nobody’s perfect; no further comment). When it comes to this band specifically, well, they call their style Roman Catholic Black Metal.