It's been said before but I'll say it again — ever be so deeply, permanently emotionally destroyed by killing your best friend in the name of the newfound necromancer/cavalier relationship that you build a house that treats cavaliers as innately disposable, breeds them for a single purpose, genetically matches them to babies before they are born, names them for sacrificial animals, specifically so none of the necromancers who follow behind you will experience the heartbreak of losing the person they love most in the world, so horribly that they can't stand to hear their name spoken aloud for the next ten thousand years, only for the scion of that house, ten thousand years later, to be so revolted by the concept of killing his cavalier for Lyctorhood, so disgusted by your crime, that he claims G-d's directly expressed will is heretical and fundamentally morally opposed to the principles of the religion you helped to found?
And then, when that person does do what you explicitly built his house to be able to do and uses his cavalier as a tool rather than a person — even if he does it because he believes his cavalier capable of surviving anything, the polar opposite of what you tried to teach his house to believe — he experiences his cavalier's death as such an abrupt and horrifying loss that after he himself is killed he wanders the afterlife in grief, impotently taking revenge on a woman who should have been burned up for Lyctorhood by the person who loved and needed her most, but was spared, saying may all the blood of your blood suffer even a fraction of what I have suffered? The suffering you tried so incredibly hard to insulate him from? He of the church you built to bury the memory of a nun?