The Thais Lighthouse is located at south-west of the Thaian depot. It seems to be a lighthouse for ships aboarding nearby the coast. In the first floor, it says that it is forbidden to turn the lights off. Mainly decorative, it's just a tower, with a coal basin on the top.
In the underneath, however, there seems to have been someone who was greatly interested in enslaving Cyclops in the basement of this lighthouse to force them to forge powerful weapons for his evil plans.
Due to the invasion of orcs within the perimeter of the Thais city, sometimes there are outcasts spawns inside the tower, including Orc Warlords among others. But it's not regular.
It's located here.