It could be argued that the Black Templars are the most zealous of the Space Marine chapters (who are all pretty fanatical, being honest). As such, their chaplains are some of the most religious of them all. And they're getting some new stuff in the upcoming Black Templars codex. Have yourselves a look.
From the article:
The Emperor’s Champion is often the star of a Black Templars army, but they wouldn’t be anyone without the Chaplains who arm them – mentally, physically, and spiritually – for war. A number of classic Chaplains are making their returns soon, while the stunning new version of Grimaldus – and a bunch of other Black Templars kits, too – are available to pre-order this weekend. This being the case, we’re putting the spotlight on these righteous heroes of the Reclusiam to show how integral they are to Dorn’s crusading sons.
The Chaplains of the Black Templars are true paragons of the Chapter – their zeal and determination are beyond reproach, and their hatred of Humanity’s enemies absolute. In this, they stand apart even from Chaplains of other Chapters.
While most Space Marines revere the Emperor as a great and powerful man who has rightfully earned the respect and adoration of the Imperium’s countless citizens, to the Black Templars, he is truly divine – a God-Emperor to be venerated and worshipped. This surety of faith sees the Black Templars Chaplains fight and preach with a religious fervour that is unmatched.