- Country: Located in::Drachensgrab Mountains
- Leader: Grand Master Graylen
- Population: Population::0
The Obsidian Tower is located in the Drachensgrab Mountains, and is home to an order of mages dedicated to protecting the Flanaess from extraplaner invasion.
Storm Tower was an ancient keep that was built atop the ruins of an ancient Flan stone circle. It had long been the focus rumors about strange, mystical happenings. Research by the Griffin's Guild senior mage, Robertson, revealed that the rumors were true. The tower had been built upon a ley line, and controlling it could give the guild access to the power it needed to liberate the Pomarj. Secretly, Robertson also hoped it would provide the key to defending Oerth from the growing threat of demonic invasion.
Robertson gathered around him loyal followers to penetrate the depths of the Tower. They were successful, and Robertson convinced the other founders of Obsidian Bay to build the fortifications of the city to protect the tower. They renamed Storm Tower Obsidian Tower, and Robertson and his followers became the first Mages of the Obsidian Tower.
In CY 587 the Scarlet Brotherhood invaded Obsidian Bay, and were eventually able to hold it for several years. As the city fell an assault on the Tower launched by seven ancient Suel Archmages whom members of the Blackrazor Guild had unwittingly freed. The assault apparently triggered some sort of magical defenses in the tower, causing it to teleport to an unknown location in the Drachensgrab Mountains. A subsection of the tower, now known as the Ruins of the Obsidian Tower, still lay in Obsidian Bay. They contain several levels of dungeons, all carefully protected by powerful magic aimed at keeping intruders out ... and the denizens of those dungeons in.
Technically the 13th floor of the Obsidian Tower, Obsianus House is a private four-story manor house located in Sigil, City of Doors. The House can be found in the city's Guildhall and Markets Ward.
- Mages of the Obsidian Tower: An order of mages dedicated to protecting the Flanaess from extraplaner invasion.
- Obsidian Guard: The Obsidian Guard were once a proud and prestigious military force culled from the finest members of Obsidian Bay’s citizenry. For over half a century, their sole purpose was the defense of the Obsidian Tower.
- Graylen, Grand Master of the Obsidian Tower
- Robertson, Founder of the Obsidian Tower
- Starstorm, former leader of the Obsidian Tower
For the remainder of the roster please see: Mages of the Obsidian Tower.