Guilcera was facing a peaceful era, by grinding infinite experience the citizens cleared it's land from the evil beings that once were a plague. People were really bored and despite some random powerful dude going rampage and killing some people before committing suicide, nothing really was happening. People accumulated so much wealth to the point that gold worth nothing due to inflation. Everyone's favorite activity became to talk nonsense in front of the depot.
Well, actually not everyone's. Remere was a curious guy. He was messing with weird magic artifacts, and ended up discovering how to open portals to other map dimensions. Despite being successful, it was dangerous and he was not really sure of what he was doing, and the full potential of the artifacts and magic involved. He ended up opening a breach to Tibia map, from where Tibian gods emerged from. They didn't like to see a map the resembled Tibia, and went full wrath into Guilcera map, claiming it to not be the real thing, filthy and unworthy