The lower plane, sectioned into nine layers, inhabited by the devils of lawful evil and destination of lawful evil souls
It is the ultimate plane of Law and Evil, the epitome of premeditated, crafted cruelty. The devils of the Hells all obey a higher law than themselves, but all that really means is they chafe and rebel in their caste. Most undertake any plot or action, no matter how foul, to advance themselves. At the very top of the heirachy is Asmodeus, who has yet to be bested. That is the law of the Nine Hells.
The Nine Hells compete with anoy other lower plane for their sheer diversity of vileness. Devils are more cunning, more subtle, and more dangerous than any other fiends - so they say. A demon revels in slavering, insane, evil power, but a devil always has an agenda, a plan of attack, and a carefully conceived plan for retribution if necessary.