Hows that? The closest thing I can think of is the obyriths-
[sblock]who, as described in Demonomicon, are beings of evil incarnate, created the demons via the shard of absolute evil, and created the devils via corrupting Asmodeus.[/sblock]
They show up in the service to Phraxas, the Demon Lord of the Blood Rift. He's reguarly attended by a pack of Baernaloth Viziers. Represented, stat-wise, as minions, which may be what some might be upset by. Admittedly, they might be the highest level minions in the game, so they remain epic in scope - they are only minions in the context of a fight with 30th level PCs, basically. You could easily conceptualize some standard monster stats for them as appropriate mid-high epic monsters, since they have a bit more interesting abilities than most minions.
(Their attacks inflict significant ongoing damage which only ends, I think, when the victim gets far away from enemies, or allies, or some such condition; also, when missed, they pull a vanishing act as they go invisible and teleport away.)
That said, they don't get much discussion of them in detail, so one can decide more about who these Viziers might actually be or why they are there - are they just lackets of Phraxas? Are they secretly manipulating him for their own ends? They aren't really focused on, which gives the DM more room to adjust the situation to their own ends.
Which left me wondering- how does "Asmodeus was cast from his master's palace in Baator for excessive brutality and indiscriminate killing, along with all his followers, and they landed on the fields of Avernus, broken in mind and body" in The Plane Above, combine with the story in Demonomicon?:
[sblock]In which he was the eternal guard of Tharizdun's prison, Pazuzu got him to believe his god was bad for giving him this thankless duty, he abandoned his post, and went into the Abyss to carve a chunk of the shard off, fashion it into the Ruby Rod, and led an army into his masters home, before killing him with the ruby rod.[/sblock]
Maybe he was cast from the palace, then later forgiven when Tharizdun was finally imprisoned, and set to guarding him?
Or some other combination?
I liked almost all of the fluff in Demonomicon, but this somewhat bugged me. They've been pretty inconsistent about Asmodeus's backstory, and I get a bit more disappointed with it each time - it was great to start, grew weaker with the Plane Above, and is now just muddled with the Demonomicon. That's pretty much the only area I've run into where 4E gets confused like that, though, and the rest of the book is so good that I'm willing to give them a pass.