The Tower of Advent
An eldritch tower piercing the sky that mysteriously appeared in southeastern Frigus. It resides on an island off the coasts of Niflheim, waiting for visitors to enter its gates and clear its 100 floors.
The Tower of Advent is one of, if not the strangest entity in all of Sagrea. Every time people attempt to study or explore it, nothing about the tower will ever be consistent or plausible. Mappers turn out to have completely different charts, even if they were on the same floor, adventurers occasionally report finding less than or even more than a total of 100 floors (that may or may not be bigger than what the tower could possibly hold), and just about anything can occur within the walls regardless of what is realistically plausible.
One widely accepted, yet ultimately inconclusive theory is that somehow, the tower itself is alive. It seems as though something is possessing control of what occurs within and that they may be the same entities that instigated the Advent of Ambition. The tower promises three wishes to anyone brave enough to reach its peak, but it is entirely unknown if any victors have even had them granted at all. One thing is certain, though: whatever the Tower of Advent is, it clearly takes great pride and a sadistic sense of joy out of toying with its visitors.
Architecture
The strange architecture of the Tower of Advent is completely unlike anything else in Sagrea. Its outer walls are composed of a strange, indestructible material resembling various metals. The building itself has various floating rings encircling around it, presumably made of the same "metal", along with other alien forms of geometry that leave the mind boggled. The inside of the tower, however, is completely unstable. Nothing except the top floor is set in stone, and the building decides what the visitor will see, with every floor being different from the last. In addition, the floors themselves do not conform to the actual shape of the tower; those that make it out alive reported floors that seemed like an entirely new world, and just about anything could be on them, from a floor consisting entirely of a single city or even a forest.
Creator of Araea, Megacorpolis, and many others.