The Dying Age
The Diabolist of the Clockwork Fortress controls fiends and tampers with forces even the Archmage avoids. He likes his victims screaming and his chaos pure while claiming that the demons he summons would otherwise overwhelm the Great Gold Wyrm who seals the Abyss. There are three differences between him and his demons: first, he likes keeping destruction personal rather than universal; second, he’s capable of kindness, so long as it comes as a great surprise; third, he holds landed title within Infernus as a Duke of Hell by right of conquest.
The longer he lives, the more this Diabolist looks like one of his demons; a frightening thought, given that this Diabolist Ascended to the title within the past three years. The stories are that he was originally a human man chosen to be the Mortal Sword of The King of Winter, but you’d be hard-pressed to prove it.
If the Diabolist has overarching goals, they are obscure. What’s clear is the delight he takes in wielding power and unleashing chaos. His enemies say that he may be nothing more than a slave to the vast powers he dares to command, but as long as he’s smiling he seems to have the upper hand.
The Diabolist leads a scattered and half-mad crew of fiendish cultists, and maintains a small army of clockwork soldiers. They adore him with respect that borders on worship. In turn, he alternately exalts them and brings them to ruin. With his 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. He is in it for himself, and he indulges even his petty whims. If he remained on-task the way the Crusader does, things would doubtless be a lot worse. Unless indulging his whims is actually part of a subtle plot that none can guess at until it is too late.