The Nine Hells

The Nine Hells are the lawful-evil plane of devils, stacked in nine layers from Avernus at the top downwards.

Campaign 1. In August 2020 (real date), standing over the carcass of a "Demon Lord(ish)" and holding soul coins, Braggum mulled over owning real estate in the top layer of hell (C1 · Monday 10 August 2020 · A demon lord's carcass).

Campaign 2. A library haul in 1034 PC included Tyrants of the Nine Hells, a halfling mage's first-hand account of some of its layers (Anaxis). From mid-1034 the party planned to "go to Hell" to deal with Thekelan and check on Glix and Glux. The tuning fork kept in The Chest of Great Treasure let them plane-shift there. Torganoth's contract offered safe passage onto God Street and protection from the eyes of Dis (C2 · Wednesday 9 November 2022 · Torganoth's contract), and late in 1034 the party recovered The King In Yellow's contracts in Dis (List of Contracts).

Campaign 4. In 1047 PC Uldrick's commune with the Amber Queen said that answers about devil contracts lie in the Iron City of Dis. The Baron wants to buy out his own contract, which would mean travelling to the Hells (or dealing with Heishen the Deathless), and the party learned that Asmodeus owns the contract behind the corruption under the city.

Reaching it. By a ruby colour pool in The Astral Sea, a red and black curtain in the Deep Ethereal or a plane shift fork of iron tuned to F♯.