What follows are some thoughts on Infernal Distinctions (and how to make them into more than just a free attunement).
The Knight’s Fee
Upon being elevated to knighthood, a demon may lay claim to an estate (or fee) within their Prince’s domain. The size of estate will depend on the region of hell. A Knight in Sheol or Abaddon might have a creepy if stately manor, while one of their peers in Shal-Mari would be lucky to claim a storefront or penthouse apartment.