Fort of The Fallen

Note: This dungeon was originally named as "Castle of the Fallen"

A large dungeon, which spawn mid-air in between the clouds and the ground. Legend says that these floating structures house celestial beings that were banished from heaven.

Strategy
As the player will get Mining Fatigue when he gets higher than certain level of the structure, the only way for him to enter the place is through the sewer, which is the part where water flows out. There will be Iron Bars blocking the way, but since the player will not get Mining Fatigue until higher up, he can break his way through and swim through the lower part.

Spawning
The spawning coordinate for the Fort of The Fallen is above Y=80 and below Y=127 (Clouds), or whatever Y coordinates that makes it not close to the ground and not touching the clouds.

Will not spawn in the following biomes: Most likely to spawn in the following biomes:
 * Extreme Hills
 * Mega Taiga
 * Desert Hills
 * Forest Hills
 * Ice Spike Plains
 * Or whatever biome that generates high terrain
 * Plains
 * Ocean
 * Deep Ocean
 * Or any biome that generate low terrain

Mobs

 * Dark Angel
 * Spider

Boss Mobs

 * Dark Archangel