From the White Wolf Wiki, the most complete White Wolf reference

The Acharne is a faction originated in the Hellfire Clubs of Europe and the Americas. They use mutilation rites, indulge in intoxication and damaging drugs, and practise painful mind-games among those they encounter.

They move among the subcultures, in particular the Gothic movement, but are easily set apart from other Cultists or the Hollow Ones. They believe the Code of Ananda is a weakness and practise Mind in pursuit of mastery. Most other Ecstatics consider them dangerous.