On the level you visit after killing Lucifer, you are confronted with every demon lord who has not yet been killed. But when they appear here, they have special AI: they cannot covetous warp, and grudge each other as well as you.

Add a system of “hell curses”. When you enter a demon lord’s lair, you are afflicted with 2 random curses, which stick around forever until the lord is killed or bribed off.

You can receive at most six curses over the course of the game, requiring you to defeat the lords of the first three lairs you encounter. Further generation of lairs does not add any curses.

A non-comprehensive list of potential curses is:

• healing potions heal only half as much HP
• your speed is knocked down by 2
• your AC is deducted
• your spellcasting failure rates increase
• you are randomly inflicted with confusion every 50 turns or so

A demon lord who occasionally summons demons (or some other sort of minion) and, when killed, will possess the body of one of his minions, so you need to kill all of the summons before he can be finally killed.

Add a unique lich or demon lord enemy who may appear as a side effect of raising the dead with the Book of the Dead. Not specified if this is the only way this monster can ever appear, or whether other mechanics like demon gating could bring them in as well.

Restructure Gehennom to be very short, containing the Valley, the three Wizard’s Tower floors, and a “nexus” floor at the bottom, containing the vibrating square and four magic portals, each leading to a randomly selected demon lair.

You can only enter each lair once: you must decide whether to attempt defeating the demon lord or not before leaving. The exit portal won’t work if invocation items are left behind. The demon lords are beefed up from vanilla, and are not bribeable since they’re not guarding access to the stairs to extort passage.

As incentive for defeating the demon lords, they apply debuffs on the ascension run, described in #3396.

Shorten Gehennom drastically, paring it down to a few mandatory levels (the Valley, the Wizard’s Tower (containing Vlad’s Tower entrance), the vibrating square level containing the fake Wizard’s Tower to portal into the real one) with no demon lord lairs and no filler. In exchange, once you start escaping the Sanctum with the Amulet, any level you reenter for the first time gets partly overwritten with Gehennom elements – rivers of lava, twisted mazes, and in particular, the demon lords. However, enough areas of the map will be left in their original states so that it remains recognizable. In particular this is aimed at making sure any stash you have made may not survive the process.

There are several motivations for this:

• Reduce the common feeling of “the game is over after the Castle” by putting only a few things between the Castle and the ascension run.
• Put the main challenge of Gehennom on the way out of the dungeon, not on the way in.
• Make it uncertain that the player will be able to go back to a big stash of items after grabbing the Amulet and take whatever they need before entering the Planes.
• Reduce the number of situations where the player can simply levelport away from a hairy problem such as a tough demon lord, collect the appropriate gear to fight them, and return (dipping into and out of Gehennom).
• Remove a Gehennom-worth of items the player finds on the ground and in monster inventories (where “the difficulty is flat but the loot keeps coming”).
• Mitigate the tedium of knowing you’re as powerful as you’re ever going to get but still have to retrace 50 explored levels. Relatedly, remove the incentive – the ability, even – to go tunneling through mazes.

Some of the non-guaranteed demon lords (provided they aren’t prematurely summoned into the game) show up randomly in Gehennom on the ascension run.

Demon lords should be made really powerful but each have their own particular weakness or Achilles heel that allows a prepared player to fight them effectively.

Add a system for casting ritual spells: more powerful and more expensive spells which have some esoteric effects you can’t get otherwise. The main differences between ritual and normal spellcasting are that they consume valuable, hopefully non-renewable components, take a number of turns to cast instead of taking effect instantly, and may require you to be in or set up certain circumstances.

Various ritual spells that have been proposed:

• Ball spells which consume a gem as focus and create a ball of elemental power that hits surrounding squares but not you. (Long casting times would probably make rituals infeasible for combat though.)
• Temporarily increase your carry cap by a great amount. (Other new intrinsics as required.)
• Resurrect a corpse as a tame monster (necromancy).
• Grant temporary intrinsic life saving.
• Single controlled polymorph with a greatly increased duration.
• Summon a demon, demon lord, or demon prince. Requires 5 cursed candles and a marker (to draw the classic pentagram). If summoning a named demon lord, it’s either random or there’s some expensive way to control who shows up. The demon lord could be peaceful, but with current behavior this is useless. Possibly summoning them allows you to make a pact with them.
• Remove the graveyard status from a level (would need to be expensive, and perhaps involve the Book of the Dead, and multiple different headstones).
• Grow a tree. This consumes at least a piece of fruit. For anti-farming the tree should probably not produce fruit or bees when kicked.
• Create a portal between two levels of your choice (doesn’t work with the Amulet obviously, but otherwise works)
• Create an artifact (that is, you somehow imbue an item with properties it can’t normally get).
• Bless items. Consumes a blessed scroll of remove curse.
• Genocide a genocidable monster. Consumes a figurine of that monster plus other costly things.
• Reverse genocide a monster. The monster may or may not have to be normally reverse-genocidable. Consumes a figurine of that monster plus other moderately expensive things.
• Charge something. Requires a rare ingredient - perhaps a dilithium crystal.
• Summon tame elemental(s). Among other things, ingredients include: a potion of water, any beatitude (water); a rock (earth); lit candles, a lit oil lamp, or a lit potion of oil (fire); an amulet of magical breathing (air).
• Create a magic lamp. Needs an oil lamp (of course) and a figurine or mask of a djinni (or possibly a nearby live djinni).
• Make the current level non-teleport. Requires a scroll of teleportation and that the caster be standing on an anti-magic field at (?) either the start or the end of the ritual.
• Create a fountain. Requires a statue of a medium-sized or larger monster, which gets destroyed (by turning it into the centerpiece of the fountain). There may be potential for wishing abuse; perhaps the fountain should be flagged so that it can’t produce a wish-granting water demon.
• Turn a regular knife into an athame. Components include other bladed weapons with positive enchantments adding up to 20 or something; all of these charges will be drained to +0 in the creation of the athame. The resulting athame is +0, regardless of the charges on the component weapons or original knife.
• Create a tame golem or golems. Requires a large amount of total weight of objects made out of the golem’s material.
• Summon a coaligned angel or other minion of your deity as a pet.
• Create a tame wood nymph from a tree (only once per tree).

Ritual spells come in spellbooks like usual, but aren’t stored in your spell list. Instead, reading the spellbook prompts you if you want to begin its ritual and tells you the necessary ingredients and circumstances you need to satisfy as preconditions. If you meet all the conditions and answer yes, you initiate the ritual. (For simplicity, this should probably burn up / expend all the components instantly.) You cannot begin a ritual while in the process of casting another ritual; this should probably be implemented as a precondition.

Apart from the component cost, rituals act as a constant drain on your Pw until the ritual is complete. If something distracts you in the middle of the ritual, you can go take care of it and then resume the ritual as long as you have the Pw left to finish it. (You could also drink gain energy during the ritual.) The only way for a ritual to fail, possibly backfiring with bad effects, is for you to run out of Pw while it is incomplete.

In addition to its preconditions, each ritual also has some postconditions: common to all rituals is that you have been casting the ritual for at least some length of time, but there may be others, such as standing on the square where you began the ritual, or have another item, or kill a monster, or something. There may also be other conditions such as “moving off the space where the ritual started breaks and halts the ritual”.

Every time you stop casting a ritual (whether it succeeded or failed), it increments the spellbook’s spestudied field; the book will eventually disintegrate after casting it a certain number of times.

Rather than giving each demon lord a fixed weapon with a fixed set of artifact effects or object property, create a set of powerful weapons that each demon lord randomly gets one from when they generate.

This might not apply if a demon lord has a strong lore reason for a specific weapon, such as Yeenoghu wielding a flail.

A cursed magic lamp may generate a demon lord (possibly pacified) instead of a djinni when rubbed. Possibly you could read the lamp to see the name of the demon lord it contains.

When you approach Mephisto and he is still peaceful, he does not demand tribute to pass like normal. Instead, he offers to buy your soul in exchange for powerful assistance on your quest to get the Amulet. If you agree, you are given amazing combat advantages (huge intrinsic damage boost, huge intrinsic AC boost, etc).

One of two bad things can happen as a result:

1. You have some chance, maybe 1/3, of failing to ascend when offering the Amulet to your god, as Mephisto claims your soul (the god still gets the Amulet but cannot raise you to immortality, so it’s a weird “win” that is not an ascension).
2. While ascending through Gehennom with the Amulet, he may reappear and try to take it and everything else for himself. All buffs he gave you are instantly removed and perhaps some debuffs are even applied. Possibly, defeating him in this circumstance could yield your soul back.

Alternatively he might appear on Astral, but that could be hard to explain flavor-wise. Or just create some test for if the player is in a sufficiently dire condition, and when they are he claims the player’s soul.

If you already have the Amulet the first time you meet Mephisto, he may not offer a bargain at all.

Split Gehennom into two different branches - Hell, which contains devils and the lawful “demon” lords like Asmodeus, and the Abyss, which contains demons and the chaotic demon lords. Either only one of these generates in a given game, or the player gets a choice of which one to go to in the Valley of the Dead. Alternatively, they’re sequential parts of Gehennom, with the Abyss being deeper.

Revamp Gehennom by making its main branch substantially shorter, a “hub” branch containing stairs or portals to a bunch of sub-branches containing demon lords’ lairs. Most of the lairs are optional, but at least some of them are required in order to enter the Sanctum. Each demon lord that you don’t kill, however, incurs a unique, harsh effect or debuff on you once you have the Amulet. Suggested ones include:

• The mysterious force, as it exists in vanilla.
• When you try to ascend the stairs, they vanish and several illusory copies of stairs appear across the level, along with one real one which you have to find.
• Walls extrude from existing walls around the hero in random directions, never entirely closing off, via a cellular automaton that looks for walls with a 3x2 area of walkable spaces in front of them, with the space directly in front a regular floor space - the effect of this given enough iterations turns the terrain around you into a maze.
• Generic damage over time, not severe but enough to provide a headwind. Or partial or total disabling of natural regeneration.
• Asmodeus: Some damaging cold effect that happens periodically, or your cold resistance is nullified and replaced with a vulnerability to cold effects.
• Baalzebub: Something to do with insects, either periodic summon insects from nowhere or stronger/more frequent insects
• Juiblex: You may randomly become ill, or have your regeneration dampened or something
• Geryon: Hordes of buffed q generate and rampage periodically.

If you approach a demon lord with a low amount of gold, they automatically become hostile.

Add multiple sub-branches of Gehennom, each containing a single demon lord’s lair. Killing them is optional, but each one that remains unkilled provides passive effects to thwart the player within Gehennom, especially on the ascension run. The mysterious force could be one such effect. The idea is that it’s not feasible to skip them all in a normal game because the combined effects are too difficult to overcome, but not necessary to kill them all either. You are able to choose which effects you want to put up with.

You can’t levelport down past a demon lord lair if the demon lord is alive and well on that level. (If it hasn’t been generated yet, it’s assumed that they are.)

New “doomed” intrinsic, which can be given by late-game things such as demon lords (via something like SpliceHack’s dark speech). This intrinsic causes your Luck to be counted as -10 as long as it is active, overriding your actual luck and any luck items you have, not timing out. (It doesn’t actually change your Luck stat; just makes things that check Luck return -10. When it wears off your Luck reverts to what it was normally.)

If you bribe a demon lord with less than 1000 gold pieces, a Wizard-style periodic timer is started, except that every time the timer triggers random demons will be spawned around you. The demon lord itself may return, hostile this time.

A chaotic Cartomancer who performs a same-race sacrifice gets not a peaceful Juiblex or Yeenoghu, but a card of summon Juiblex or Yeenoghu.

When the demon lords all levelport away into Gehennom on the ascension run, they always land on the downstairs rather than being randomly placed, because they’re smart enough to lie in ambush for you.

You cannot levelport down past a demon lord’s lair level until the demon lord is killed, appeased with a bribe, or otherwise gotten rid of. Attempts to levelport past it will just land you on their lair level instead. However, you can still go below the level by way of the stairs, a hole, or a trapdoor in the lair.

Level flag that prevents mapping as long as the local “boss” is alive (nemesis if anywhere in the Quest, demon lords/Croesus on their own levels). Maybe make the ‘nommap’ field 2 bits instead of 1.

Place a statue of every demon lord who has not yet been generated lining the walls of Moloch’s Sanctum. This way, if you really want to fight one (or all) of them, you can do so.

Change covetous warping so it only works for demon lords on their lair levels, and then they can only warp back into their lair.

Demon lord who has no real special abilities, but has a very, very high physical damage output. Or give one of the existing, uninteresting demon lords a high physical damage output.

New demon lord with a fire attack comparable to Asmodeus’ cold attack (this is actually already implemented, but is unused). It seems weird that no demon lords are really associated with fire.

New demon lord who spellcasts, favoring touch of death and summon nasties. However, the only thing it summons and gates in are incubi and succubi.

When you kill a demon lord, its lair becomes diggable.

Soul selling: when you summon a demon lord, there is some opportunity for you to sell your soul to them in exchange for a wish.

• Selling your soul both angers your god and suppresses all interaction with them.
• You may be able to recover your soul by killing the demon lord; for balance the demon lord should go far away when you sell your soul, though not out of the game.
• Alternatively, unless you wish for nothing (which makes the demon lord vanish forever), the demon lord will immediately become hostile, making it an unlikely tactic in the early game.
• Entering a temple without your soul will immediately anger the priest.
• Your quest leader won’t let you go on the quest while you are soulless.

Chaotic same-race sacrifice demon summoning causes the demon to give you a nice item or some gold when they appear.

You can make deals with demon lords (or maybe just one demon lord) for special abilities, but this has major drawbacks.

A demon lord who lives in Gehennom who you can sell your soul to in order to gain levels. This will have drastic effects on your score (or something) at the end of the game.

Demon lords that accept a bribe don’t actually go anywhere. They get out of the way to the stairs if they were previously in the way, but otherwise they have their movement points set to 0 and cease warping for as long as they are peaceful.

Restore the Amulet Delivery Service to the game: demon lords in the Sanctum, but not the Wizard, will fight the current holder of the Amulet of Yendor for it. Only do this if lugging a demon lord down to the Sanctum is considerably harder than just fighting through the Sanctum is itself, and no demon lord is actually guaranteed to win against the High Priest.

The demon lords take no interest in you until you are on the ascension run with the Amulet. At which point they attack.