I am currently running an Out of the Abyss campaign for 5th Edition Dungeons and Dragons. The group has gotten pretty far, they have
taken out Zuggtmoy, Jubilex, Yeenoghu, and Baphomet. These four Demon Lords were trying to take each other out (Baphomet and Yeenoghu; Zuggtmoy and Jubilex) so they were not actually at full power.
I am also straying off the book a bit as most campaigns do with the choices of the players.
I feel they haven't really been challenged yet with the exception of
the battle between Yeenoghu and Baphomet as there were Gnolls and Minotaurs going at each other and fighting the group which helped make it more of a challenge (a couple of epic fails helped kill off a person which also added a challenge).
I was hoping that the remaining Demon Lords had a lieutenant of some sort and/or if they have been known to have a type of body guard or certain type of follower. I know Graz'zt has his right-hand man Verin. Does Demogorgon and/or Orcus have a favorite minion or lieutenant? If not I am going to make up some kind of bodyguard type. Is there a certain race/sub race (like Balor or Succubus) that these three specifically favor these two Demon Lords? Probably for the sake of the question title and future use, do the other Demon Lords in Out of the Abyss
(Fraz-Urb'luu, Zuggtmoy, Jubilex, Yeenoghu, and Baphomet)
have a lieutenant, favored minion, or specific follower race?
On the wikis that I have read there isn't a specification or mention of anything for lieutenants. And that there isn't a race specifically designated to the demon lords. I know Orcus has his army of the undead, so I am guessing he doesn't care about race.
I am not looking for anything 5th edition specific. If there is lore from other D&D editions or even other mythology sources like Pathfinder that would answer the above I am fine with it. Hopefully this isn't too confusing or too long.