I'm playing through this time with MaxQuest and AndreaColumbo's excellent mods that add in Pillars 1 items to Deadfire. I just ran across the Belt of the Royal Deadfire Cannoneer, and I'm trying to think of uses for its Firebrand weapon -- which isn't just accessible to Druids! Any ideas about how to build around it, or uses for it? Bonus for ways to use it with the existing companions/sidekicks. Obviously, you can use the Ring of Focused Flame with it; and I saw from some older posts Boeroer's idea that using the Ring with it would offset the accuracy loss of the greatsword modal, giving extra damage. Any other synergies or builds?

Monk for turning wheel bonus, that grows with wounds coupled with helwalker might boosts

paladin for flame of devotion - eternal devotion and scion of flame

Devouted fighter obviously

Chanter with Aefyllath Ues Mith Fyr and rapid casting access

I loved this belt and firebrand with a solo monk in PoE1 using torment’s reach, which was way more powerful in that game.

For existing party members in PoE2, how about Aloth as off-tank/striker?  (See the Arcane Master build in the St*am forums.) With boots of speed and other speed buffs, the magnificent escape cape, Aloth can make good use of the belt’s other spells without blasting the party. Add scion of flame and the ring of focused flame and things will scale nicely.

I can't think about Firebrand without thinking about Boeroer's build The Cauterizer, which i loved in PoE1. Maybe you can emulate it in a viable way considering a lot of the Barb passives are still consistently there? Personally my attempts to run solo SC Barbarians in PoE2 haven't been very convincing. This could be the secret sauce that brings a fiery barb build together.