Dark Tower is a type of dungeon added by the Twilight Forest mod.
They are colossal towers and can only be found inside of a Dark Forest. There are many unique floors and themes with obstacles, treasures and monsters inside. The entrance to these towers is made up of Reappearing Blocks. They resemble Lich towers but are much larger and made up of different types of Towerwood. The main feature is the deadly Ur-Ghast, a boss that will be found at the top of the tower if not previously defeated. This structure is essentially a giant puzzle.
Players may also find Netherrack, Soul Sand, Nether Wart, Redstone Lamps, and more. Some of the towers connected to the Dark Tower are also made out of Netherbursts.
The rooms may contain monster spawners and unique treasures such as Enchanted Books, Steeleaf, Ironwood, Redstone, Diamonds, and more. One special treasure that you can find in these chests are Tower Keys. In order to travel to the top of the Dark Tower, tower keys must be found before venturing onward. (unless, of course, you have a longhook or manualshoot, which you can use to grapple up). On the second to last floor before the roof is a Carminite Reactor, which can be activated by turning on all of the levers nearby.
The mobs that inhabit the Dark Towers are Skeletons, Creepers, Endermen, Blazes, Pinch Beetles, Carminite Ghastguards (spawning outside the tower, mainly at the top), Carminite Ghastlings, Carminite Golems, Towerwood Borers, and Carminite Broodlings.
The peak of the Dark Tower is covered in Netherbursts and is home to the Ur-Ghast. The Ur-ghast is a large creature with long tentacles with blood on them. The Ur-Ghast will fire fireballs, summon minions, and stay at the peak of the Dark Tower until defeated. Upon the Ur-Ghast's defeat, a treasure chest will spawn in the middle of the peak containing valuable treasure. Occasionally, multiple will spawn.