Essentially, there are two basic types of magic; White Magic and Black Magic, and each spell is aligned with one or the other. White Magic never counts towards magic addiction. Black Magic is another story. One can never entirely cast Black Magic safely, even a single spell can have corruptive influence.
Every Black Magic spell a character casts will give them Black Magic Points or 'BMP'. The number of points each spell cast will add is dependent upon both the PL of the spell and the willpower of the caster. If the PL of the spell exceeds the character's willpower then they gain Black Magic Points equal to the PL of the spell. If the PL of the spell doesn't exceed the willpower of the caster then they gain half the PL of the spell in Black Magic Points, rounded down. Therefore, if a Black Magic Spell with a PL of 4 is being cast and the character has a willpower of 5, they would gain 2 Black Magic Points. If, however, their willpower is 3, they would gain 4 Black Magic Points.
Once a character reaches 10 Black Magic Points, they need to make a willpower test to check against Magic Addiction. This willpower roll is not doubled and the target number is is the amount of Black Magic Points accrued. If the test succeeds there are no ill effects, but the Black Magic Points do not go away. This means another test will be necessary the next time a Black Magic Spell is cast. If the test FAILS, one point of the Addiction Drawback (magic) is added to their sheet. If an addiction is already present, another level of the drawback is added. This applies up to addiction 6. Black Magic Points reset each time an addiction level is added.
If the roll fails and the witch is already at Addiction 6, she has been overtaken by the power of the Dark Arts, requiring Staff involvement.
Like any other addiction, Magic Addition can be worked through, but it isn't easy. If the Witch only has Black Magic Points (IE, no addiction yet), those fade at a rate of 1 point for each week that the Witch goes without casting a Black Magic spell. So, 3 Black Magic Points will take 3 weeks to fade completely. However, if the Witch has any Magic Addiction levels, it requires 1 week of casting /no magic at all/ to reduce the Addiction by 1 level. /Any/ spell cast while suffering magic addiction, even White Magic, immediately starts the clock over.
