Why did this Finnish black metal band never get the exposure needed?
Did anyone? You would be surprised how few people even remember Demigod... and in black metal (cf. Beherit), for mostly image-related reasons, exposure was negative back in the day.
I think they could have been another Amorphis or Sentenced with the "Never Again" material, but suffice to say: Lethal Records. Some bands made their own promotion and connections to the global underground but that required language skills, diligence, a "clerical" sort of attitude in general which many of these drunks and scoundrels didn't possess.
But I know disconnected occasions of Belial logo famously appearing in abandoned houses of Finnish suburbs, so it may be safe to say that private worship always celebrated this cult!