That would be character-dependent, but I think Nerezza’s would be the most interesting.
Her unhappy background has made her repulsed by venial sin. That no one has ever loved her in any capacity places her in wavering states of fear, defensive numbness, and longing. She found escape in a enchiridion (not to be mistaken with the Enchiridion) about black mages with the classic look (black ‘skin’ and glowing eyes), believing them to be superior people who converted from flesh to aether and therefore liberated of corporeal need and desire. Knowing the risks and disdain the practice of black magic, she nevertheless tirelessly pursues her goal.
I imagine her mental world would be fraught with monstrous imagery of debauchery: cold reprobates, giggling drunks, money-worshiping sybarites, Quicksand succubi who tarnish men’s virtues, and so on. If this was a playable sequence, the “boss” would be her own mother as a chilly demoness, having been one of said Quicksand succubi who left her husband for a younger man after having an affair, finding herself pregnant and sending the baby that wasn’t even his back to her ex to raise. Nasty lady.
Nerezza herself would be entombed in shadow-webbing, curled up and shivering in a featureless morass that represents her depression and feelings of worthlessness. Who can save her? Who would bother?