I was ready to *(fel-)*rush in here and speak praise of Dark Mistress Repentia and Lady Elosar as examples of Illidari affiliated Eredar(s), but I see several others have already beat me to it.
There is a precedent for it in lore. It is just about roleplaying it in a way that makes it believable. I’ll even go as far as to suggest that eredar in the illidari are on some level considered a servile, due to how it is portrayed in game.
Such stories can naturally be woven in a plethora of ways, depending on the characters at play. I know that I personally, together with my guild, have had a lot of fun storylines with our resident Eredar Sorceress.
It is ultimately all about making it exciting, and weave in the stories so that it makes sense in-world. I’ll even go as far as to argue that roleplaying an eredar has massive, and thrilling potential. All it really takes is the right group of individuals to stick around with, as a casual stroll down stormwind’s streets hardly beckons a demonic entity, something I reckon even most demon hunters take to heart as well.
Anyway, side tangent aside. Good guide! Here’s to all the riveting eredar out there, that roleplay the diabolic concept in an immersive and meaningful way. 