The Diabolist of Hell Marsh controls fiends and tampers with forces even the Archmage avoids. She likes her victims screaming and her chaos pure while claiming that the demons she summons would otherwise overwhelm the Great Gold Wyrm who seals the Abyss. There are two differences between her and her demons: first, she likes keeping destruction personal rather than universal; second, she’s capable of kindness, so long as it comes as a great surprise.
The longer she lives, the more this Diabolist looks like one of her demons. The stories are that she was originally a human woman, but you’d be hard-pressed to prove it.
If the Diabolist has overarching goals, they are obscure. What’s clear is the delight she takes in wielding power and unleashing chaos. Her enemies say that she may be nothing more than a slave to the vast powers she dares to command, but as long as she’s smiling she seems to have the upper hand.
The Diabolist leads a scattered and half-mad crew of fiendish cultists. They adore her with respect that borders on worship. In turn, she alternately exalts them and brings them to ruin. With her help, they learn occult secrets, master unspeakable magic, and gloat over the destruction of their enemies. No cultist knows the extent of the cult or its ultimate goals. It is certainly more widespread than the imperial authorities admit to publicly.
The Diabolist lacks the focus and discipline that define the Crusader. She is in it for herself, and she indulges even her petty whims. If she remained on-task the way the Crusader does, things would doubtless be a lot worse. Unless indulging her whims is actually part of a subtle plot that none can guess at until it is too late.