[@Winterwake]
Alright, then I guess the rivalry came later then. My idea so far is that this "Order of the Black Sun" was around pre-unification war under the banner of the Blackguard of Morr, an old god of Death and Dreams. They fought hard but eventually their patron kingdom decided it was better to give in to Queen Avelier rather than being slowly ground into dust, so the Blackguard was ordered to stand down and surrender. When the Queen outlawed religion there was a minor conflict with the blackguard but they eventually gave in and rebranded themselves as the Order of the Black Sun after an eclipse happened over one of their battles.

However the inner circle, [url=https://68.media.tumblr.com/589c680468a4e9c788fb8d8c2dbb7d7a/tumblr_okjhk94wM21sp8yqvo1_500.jpg]"The Black Ones"[/url], still worship Morr behind closed doors.

Functionally they do what the Silver Shields do but cheaper and offer their services for pennies when guarding gravesites.