Dariznu embodies the Pure Flame. The idea that someone could justify burning people alive as being justified by the principles of the SF is horrific. Certainly Bel Shalor is a factor, but the basic principle of the Pure Flame is to see the Flame as a WEAPON that can be used to punish your enemies. Rak Tulkhesh feeds on rage and hate, even more so than Bel Shalor; Dariznu's aggressive hatred fits with the influence of Rak Tulkhesh.
Yes, I could definitely see a campaign in which players are direct servants of Jaela trying to do what's right in the face of Krozen's pragmatism. BUT...
... The idea that you could have a story about Thrane loyalists who serve the Queen is an interesting way to dig into an almost completely ignored aspect of Thrane.
... And again calling out the fact that NOT ALL THRANES support the theocracy, even though they support the faith.
Source: Discord 7/4/2020