D&D 5E Victoro Cassalanter as a Fiend

[LordEntrails]

My party completed Dragon Heist some time ago. The Cassalanters were one of their primary adversaries. The party reveled them as

Spoiler

devil worshippers

, resulting in Ammalia and the two children fleeing town and Victoro getting captured by the authorities.

Since I love recurring villains (perhaps this is why my party rarely leaves anyone alive?!) I'm having Victoro escape Waterdeep with the help of

Spoiler

Asmodeus

. Of course that help comes at a price, and I'm thinking to have Victoro transformed into a devil! So I'm looking to create a custom NPC and would love your help.

First, I want this to be a deadly encounter for the party. It will take place in the town of Leilon and I like the idea of resulting damage to the town (roleplaying for the party to re-establish the towns goodwill!) By the time this encounter happens, the party of 6 will be level 8. They have significant magic (one very rare item each, more rare and uncommon items) and can pretty much escape/flee when needed so a TPK should not happen except in very rare situations. I want them to win, but just barely. It will be a nova fight as they will be fully rested and it will be the only encounter of the day. Probably will start with an earthquake while the party is resting for the night in the tavern.

So, for the modified Victoro, I'm thinking an Ice Devil (or Marilith) with double hit points and adding some/all of Victoro's spells including earthquake, flame strike, insect plague, dominate person, freedom of movement, prot from energy, dispel magic, mirror image. Also might add the marilith's teleport ability. And then having a summoned Barbed or Bone devil for support.

Does this sound balanced? Fun?

 

[UnknownDyson]

Mariliths are demons, which shouldn't be conflated with Devils at all. Oil and water, unless you just want to use the Marilith statblock and call it a devil. But I think there are better options available to you. I'm not sure how powerful you want the new Victoro to be or when your party will encounter him but there is a perfect Devilish form for him, and it is called Amnizu. You can change the spells to Victoro's unique spell list and leave the cleric aspect.

Amnizus - lead the infernal legions into battle and command guardians at the gateways to the Hells. Amnizus are arrogant, bullying, and ruthless, but they’re also highly intelligent tacticians and unfailingly loyal — qualities that the hellish archdukes value.

 

[LordEntrails]

@UnknownDyson Thanks. Yea, Marilith's are demons, I was looking to use the stat block, not the demon aspects . But I decided against it as it's a melee beast and doesn't quite fit. I went with the stat block of the Ice Devil, but re-flavored it to fire and added spells. Given that he will be attacking on his terms, I've laid out the plan and fight and it should be hopefully dramatic and dangerous.

The Aminzu looks interesting, but I think CR 18 will be too much. Especially if I add spells and the sort of ambush I'm planning. This will be a nova (one fight in a day, fully rested) so the party will have full resources to call upon. Here's the stat block;