Black Magic involves contracts with demons and generally involves the Black Penalty disadvantage (-3 points/level)
With every spell case with demonic assistance a 'Will + Magery - the total energy “borrowed” that day from demonic helpers' roll is made. Failure results in a level of the Black Penalty for every 10 points (of fraction thereof) by which he failed.
At 10 levels of Black Penalty all virtuous disadvantages are lost and often replaced by some dark perversions and Addiction (to demonic energies) [-10 point] is gained.
The Will + Magery roll is made at +10 but failure now costs 5 character points per point the roll is missed.
Removal of the Black Penalty per level requires a period of reflection and abstinence from all magic use and all sensual pleasures for a period of (20-Will) days (minimum 1 day) for its removal.