Devils of the Nine Hells

The manifestations of Law and Evil, the devils are the inhabitants of the Nine Hells of Baator. It is a plane of sinister evil and institutional cruelty organized in a strict caste system with a very rigid chain of command. Unlike the demons of the Abyss, the devils are highly organized in their quest for power and status - scheming and plotting power plays, coups, and assassinations.

Devils understand the failings that plague intelligent mortals, and they use that knowledge to lead mortals into temptation and darkness, turning creatures into slaves to their own corruption. Devils love to strike bargains with mortals seeking to gain some benefit or prize, but a mortal making such a bargain must be wary. Devils are crafty negotiators and positively ruthless at enforcing the terms of an agreement. Moreover, a contract with even the lowliest devil is enforced by Asmodeus's will. To own a creature's soul is to have absolute control over that creature, and most devils accept no other currency in exchange for the fiendish power and boons they can provide. A soul is usually forfeited when a mortal dies naturally, for devils are immortal and can wait years for a contract to play out. If a contract allows a devil to claim a mortal's soul before death, it can instantly return to the Nine Hells with the soul in its possession. Only divine intervention can release a soul after a devil has claimed it.

In accordance with their lawful alignment, devils obey even when they envy or dislike their superiors, knowing that their obedience will be rewarded. The hierarchy of the Nine Hells depends on this unswerving loyalty, without which that fiendish plane would become as anarchic as the Abyss. At the same time, it is in the nature of devils to scheme, creating in some a desire to rule that eclipses their contentment to be ruled. This singular ambition is strongest among the archdevils whom Asmodeus appoints to rule the nine layers of the Nine Hells.

The Devils of the Nine Hells have been at war with the Demons of the Abyss since the Dawn of Time, often dragging other planes into their eternal struggle.

Promotion and Demotion
When the soul of an evil mortal sinks into the Nine Hells, it takes on the physical form of a wretched lemure. Archdevils and greater devils have the power to promote lemures to lesser devils. Archdevils can promote lesser devils to greater devils, and Asmodeus alone can promote a greater devil to archdevil status. This diabolic promotion invokes a brief, painful transformation, with the devil's memories passing intact from one form to the next.

Demotion is the customary punishment for failure or disobedience among the devils. Archdevils or greater devils can demote a lesser devil to a lemure, which loses all memory of its prior existence. An archdevil can demote a greater devil to lesser devil status, but the demoted devil retains its memories-and might seek vengeance if the severity of the demotion is excessive. No devil can promote or demote another devil that has not sworn fealty to it, preventing rival arch devils from demoting each other's most powerful servants. Since all devils swear fealty to Asmodeus, he can freely demote any other devil, transforming it into whatever infernal form he desires

Brass Concordat
In exchange for their help against the demonic hordes the devils of the Nine Hells were granted the right to establish embassies in major cities (Brass Concordat). It is unclear how many devils actually work or live in their giant towers, but they are known to venture out into the cities (usually disguised as a member of one of the mortal races). Their motivations are almost impossible to decipher, but most scholars agree that these immortal creatures are playing some sort of long game and they often take actions whose true aim only becomes apparent after decades or centuries.