Hunting a demon king is the primary quest of the game, and ends only upon killing Richard and achieving final victory.
Complete The Hand Of the King.
Complete City Of Envy And Gluttony, go down the hole in Lord Winterfall's mansion.
Complete Mansion of Lust, and acquire the Humilitas rune, either via lewd action (requires 40 lewdness) or by paying 20 000 gold. The rune allows you to dispel the barrier around Richard's anchor.
Richard's domain is the hardest dungeon in the game, consisting of 7 floors filled with the hardest enemies in the game. Each floor is themed around one of the demon generals, and has special mechanics to match. It is recommended to have Shadowcloak II to skip many encounters. Agility 70 will also allow for completing all jumps found here, except for missing a few ether harvesting points.
At the end of each floor will be an unskippable fight that is either a fight against the demon general (if they are still alive), or a hard fight against generic demons. Each floor also requires 80 mana to open the gate to the next floor. Near the entrance of each level is a teleporter that can be activated by walking onto it, allowing easy access from the first level.
This floor is filled with various gold temptations. The piles of gold reduce willpower, the bars let you gain gold for corruption. The chests can be destroyed with bombs to weaken all enemies on the floor (recommended if you struggle against them), or looted for gold, at the cost of respawning and buffing all enemies.
The lefthand path has the fewest enemies and easiest encounters, but requires jumping.
This floor doesn't contain any negative energy point and the enemies aren't affected by the associated MATK boost.
This floor causes fire damage to the entire party with every step taken, and every turn spent in combat. The exit is located to the top right, in a lake of lava. Aside from the final fight, there are no mandatory encounters, but there is pyromantium to harvest.
There are negative energy points on this floor, but they don't give an MATK boost. Instead, they give an ATK boost.
This floor has green tiles which slow your movement speed. There are also zombies that continuously respawn from various beds and always approach to the party. If one of them catches the party, everyone is afflicted with poison and drowsy. The exit is located north from the starting area. Some encounters must be fought or escaped via flash bomb.
This floor is underwater, giving large penalties unless Aura or Slime has Air Bubble active. It is possible to skip most of the floor, either by spending 40 bombs+ by going through the middle, or by taking the righthand path if Aura has Fire III. The lefthand path has one forced encounter, the rest can be dodged with Shadowcloak.
This floor has various blockages that require the to gain cursed meat to bypass, and the Hi-Gluttony demons can use the Cursed Meat Gula spell, which becomes stronger the more cursed meat you have. It is thus advised to limit those meats in your inventory (this will also help in the final battle) The wall behind the butcher stall in the middle of the floor can be bombed to skip large parts of the map.
This floor has the Lilith fog effect, blinding the party at the start of combat, and giving the Enhanced state to all enemies. The exit is located to the north, but is blocked by a gate that requires finding two keys on the map. Alternatively the gate can be destroyed with a collar activation or 50 Bomb+. It is not possible to acquire both keys without fighting.
This floor changes depending on how Judgement Of Pride was completed. If it isn't, enemies have doubled stats. If it was completed with at least 10 justice, all enemies are disabled. The floor has several mandatory fights, including some that cannot be flash bombed. Tere are are also trollies on both the top right and top left paths that can be destroyed to skip 3 hard encounters, but doing so requires 50 Bomb+ or a collar removal.
Floor 8 has no enemies and contains only a few other harvesting points and a star metal. Continuing on from this floor is a point of no return for the end of the game. Note that you can only continue if Remove Collar is available.
The final showdown is a 3-stages boss gauntlet. As soon as you enter, Aura removes her collar, and it stays removed for the entire gauntlet, bestowing massive stat bonuses to all allies via Star Shine. In the first stage, you fight a buffed version of the Nightmare Sorceress, who must be defeated multiple times to cut down all her illusions. This fight can be quite easy as long as John has Slash III, or aura has similar AoE capabilities.
Stage 2 consists of a gauntlet of rematches against every demon general in their Hi General form. At the start of this stage, Aura is joined by lots of NPCs from Roya, who will fight until they fall, and be replaced as they do so. When all her allies have fallen, the main party will join the fight instead. How many and which NPCs are summoned depends on who is still alive, and how they feel about Aura. NPCs have some innate skills to fit their class and profession, but can also be bestowed skills from those Aura knows, although this will cause Aura to lose one rank in the skill per bestowal.
Edwin: Joins if his congregation standing is 3/3.
Julian: Always Joins.
Albrecht: Joins if Homewrecking is not completed.
Nadia: Joins if Homewrecking is not completed.
Barry: Joins unless sacrificed in Judgement Of Pride.
Duelist Quentin: Joins if defeated by Aura.
Duelist Reiner: Joins if defeated by Aura.
Duelist Ray: Joins if defeated by Aura.
Festival Adventurer A: Joins if rescued during Festival Of Greed.
Festival Adventurer B: Joins if rescued during Festival Of Greed.
Jacob: Joins if the demon was killed during Rotten Love.
Liliana: Joins if she was elected during Demon-cracy.
Sailor: Joins if he was saved from his debt during the-disbanded-crew.
White Priestess: Joins if you helped her open a church in Nephlune.
Fire Mage: Joins if you rescued her from Nephlune vault.
Fleura: Joins if you defeated as long as you did not corrupt her during Demon-cracy.
Duelist Rene: Joins if defeated by Aura and Fleura wasn't corrupted her during Demon-cracy.
James: Joins if he is still alive.
Matthias: Always joins.
Mira: Always joins.
Duelist Francis: Joins if defeated by Aura.
Priestess Elaine: Always joins.
Handsome Soldier: Joins if rescued during Slay the Demon.
Lorraine: Joins if exonerated during Nothing but the Truth.
Sathanas: Sathanas starts the battle with doubled ATK and AGI, so he will hit hard while likely outspeeding you. Sathanas will take 900 damage per turn during 10 turns and become exhausted afterwards. Bestowing Pacify or Cry of the Rooster will limit the damage you take while you bring him down.
Belphegor: Belphegor will start with a Concentrated state and boost his MATK in the first turn. It is advised to damage him with multi-hit attacks to break his concentration on the first turn. Guarding on the second turn will also limit the damage from Acedia. Beyond that, Belphegor can fall pretty quickly because of his modest HP pool and defenses.
Leviathan: Leviathan will try to take flight on the first turn, you can prevent this by inflicting him with Numb, or you can throw a web bomb after that. His crash attack can deal a lot of damage, but he can only use it when flying.
Beelzebub: Beelzebub starts with the Demonfeasting buff. Your DEF will also start with a debuff. Beelzebub has hard hitting martials with the obvious Numb counter, but you should also beware Cursed Meat Gula if you didn't throw away your cursed meats.
Asmodeus: A trick to kill him quckly is to bestow Breath of the Dragon and time an acid bomb to break his defenses when he's weak to Fire. This should deplete most of his HP. Bestowing tailwind and storm can also be helpful to outspeed him, and avoid him getting a chance to buff after bondage restraints.
Lucifer: It is possible to skip this phase completely if you let Lucifer go during Judgement of Pride. Else, the battle is against an enemy with high stats and dangerous martials. So, debuff him while boosting your own stats and use high damage combos to defeat him.