The dungeon I'm planning to do once some RTC release will allow factions would allow such endings. You would lure/drive Libby and Elsie, starting from 2 vertically opposite ends of the dungeon (Libby from above, Elsie from below), through a complex series of pits and teleporters to a great central hall, the Hall of Gor, where they and their summoned minions could fight each other for eternity. Gigglerlike small spirits would guard the eternal battelfield by picking up demon horns and iron gauntlets occasionally left behind by slain minions, and carry them to altars of Vi for ressurrection.
The player could then decide to leave Mount Anaias, or join one of the 2 sides by fighting his way through the enemies ranks to fuse their Lord. Or he could try the almost impossible by fighting both sides and fuse the other Lord too before he has made his way to the dungeon's exit after his foe had been smitten down. That would make the Grey Lord appear and end the game unless you shoot at GL before he starts speaking with you upon reaching a tile adjacent to you.
Central to the layout would be a deep chasm, deep as the long shaft in CSB; it would separate the dungeon horizontally by an irregular line of 2-3 tiles, riddled with caves, strange creatures, some flying, half destroyed rope bridges and abandoned dwarven guard houses with a series of interlinked switches. Too bad that no engine so far supports seeing what's going on on the opposite floor above/below.
Starting room would be the Hal of Gor where already some normal demons and animated armours would fight each other, later to be joined by archdemons and inquisitor knights. The eternal battlefield too would be divided by the chasm, but would have a long, narrow, unsecured bridge. It would have 2 closed and locked gates for exit. You would have to find a way to fall down bit by bit from one rock nose to the next in order to survive.
After arriving in an area that could be described as hell, the pit of FulSar, where Elsie is wandering about you'd have the choice to ascend through one of two pathes twisting the principles of the four arts. Nu, path of the knight, and Röta, path of the monk. Both would spiral up intertwined up to the top of the dungeon, the top of the Tower of KathRa, where you have to find your way past Libby and then get the choice to proceed upon two other twisted pathways spiraling intertwined all the way down: Kain, the path of the soldier, Ruin, the path of the assasin.
The pathes would be interconnected in a way similar to the pathes of CSB.
You also would have to get 4 corbums. One you'd need to restore the Spirit of the firestaff from the lava, accessible in the ruins of the Grey Lords laboratory. The other corbums would charge the Spirit of Firestaff with a limited amount of charges in respect to its fuse function, that is 1 charge per corbum (1 try per Lord

The path of the soldier would include battlefields that have many trench-like areas, where you have to do ranged combat to fight foes on the other side of chasms, while also fighting adjacent foes.
The path of assasin would mainly have riddles that aim at luring strong opponents into spots where they cannot fight back very well.
The path of knight would inlcude many fear riddles combined with hostile environment and much melee.
The path of the monk would mainly have areas riddled with shooter riddles, where you need speed, protection and cleverness to succeed.
The entire dungeon would be riddled with twisted layouts reminiscent of areas and riddles of DM and CSB, often, but not always, using this seemingly familiarity to the players disadvantage.
Yeah well that's it. Not that anyone here would ever get a bit off-topic
