The VOIDRUNNER'S CODEX is coming! Explore new worlds, fight oppressive empires, fend off fearsome aliens, and wield deadly psionics with this comprehensive boxed set expansion for 5E and A5E!
*New User*
First off, I attempted to search for this answer on Google and directly searching on EnWorld, but was not able to find anything conclusive. Searching for Blackguard + Fiend was not particularly helpful.
The description of Blackguard states they are "...no less than a mortal fiend"...