Book of ArchFeinds
Demon lord was a self-proclaimed title used by the most powerful demons of the Abyss. Though there were no formal criteria for the title, most demon lords were extremely powerful, controlled at least one Abyssal layer, and commanded armies of lesser demons. Each of them had a unique set of powers and abilities. The most powerful demon lords sometimes called themselves demon princes. Prominent demon lords included Demogorgon, Orcus, and Graz’zt
Each demon lord had a unique appearance and set of abilities and ruled over at least one layer of the Abyss. Those that controlled several layers and rose higher in power gave themselves the title of demon prince. Both “demon lord” and “demon prince” were self-proclaimed titles by those who had gained enough power and influence. The demonic fiends were in an eternal struggle, edging and fighting for dominion over one another. Unlike the archdevils, the chaotic evil demon lords did not have a rigid hierarchy, though they appeared in greater numbers throughout the Blood War.
A demon lord, when slain in a plane other than the Abyss, was banished to the Abyss for a hundred years, whereas ordinary demons, including the mariliths and glabrezus, risked being reborn into a lesser form, or not at all.
Demon lords waged eternal war with each other, often seeking ways to expand their holdings into other layers and at the same time defend their personal domains from rival lords and scheming underlings. Obox-ob was the first demon lord to hold the title of “Prince of Demons”, a coveted status symbol, followed by Miska the Wolf-Spider, and then Demogorgon. Orcus and Graz’zt contested this title, while Obox-ob desired to regain it.
Most demon lords had secretive mortal cults who sought to elevate their lords to godhood through prayer and sacrifice.
Archdevils were the greatest of devils, and the archdukes of the Nine Hells. As befitting their kind, their position was strictly dictated by the hierarchy of the Nine Hells. Only nine archdukes ruled at any given time, one for each layer of Baator. Deposed or banished archdukes were also referred to as archdevils. Prominent archdevils included Asmodeus, Zariel, and Mephistopheles.
The position of archdevils in the hierarchy of Baator was clear: archdevils were the most powerful and were, therefore, on top. The most powerful of the archdevils were the archdukes, also called the Lords of the Nine. Other archdevils were dukes, ruling portions of a layer, generals, or bureaucrats of various sorts.