Wyrm's Rock was an imposing and formidable stronghold. Its granite walls were a foot (0.3 m) thick and worn smooth from the near-constant rain and splashing from the river water. The only features were a number of arrow slits that faced outward towards the water.
Drawbridges extended from either side of the Rock, to the massive stone bridges of Wyrm's crossing. Aside from a small set of steel stairs leading up from diminutive dock, these were the only entrances in and out of the keep. In fact, all overland traffic that crossed the river at this point was forced through this well-guarded fortress.
The first floor of Wyrm's Rock was an imposing gauntlet for anyone who passed through. It was little more than a stone tunnel, standing atop big rock high above crashing waves, beset by room likely filled with men armed to the teeth. In fact these were offices for the toll-gatherers and chambers for the guards. The ground floor was marked with a hanging wooden sign emblazoned with the logo of the Flaming Fist.
Above the main tunnel was the keep's armory. It was well-stocked with all manner of weapons used to defend it from land, naval and even aerial assaults. The top floor of Wyrm's Rock served as the quarters for the officers and mercenaries that served within. 
Dug into the isle, beneath the level of Wyrm's Crossing, was the Rock's spacious dungeons. While it did include a holding cell, that were used in emergency situations only, it was really more of a storage area used to house equipment such as canoes.
The fortress of Wyrm's Rock served two main roles for the city of Baldur's Gate. First and foremost it was bulwark that protected the city from the sea. The other was as a toll-collecting site, at a cost of 5 cp, for all travelers headed north along the Trade Way.
The fort was only manned during daylight hours. At night, the drawbridges were raised and overland traffic was halted until first light next morning.
As expected, Wyrm's Rock was extremely well-defended. The Flaming Fist soldiers stationed within were equipped with vats of oil, massive rocks, javelins and projectile weapons. They could fire these out murder-holes and arrow slits while being protected behind walls of thick granite.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Ed Greenwood, Matt Sernett, Steve Winter (August 20, 2013). “Campaign Guide”. In Dawn J. Geluso ed. Murder in Baldur's Gate (Wizards of the Coast), p. 26. ISBN 0-7869-6463-4.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Ed Greenwood, Matt Sernett, Steve Winter (August 20, 2013). “Campaign Guide”. In Dawn J. Geluso ed. Murder in Baldur's Gate (Wizards of the Coast), p. 27. ISBN 0-7869-6463-4.
- ↑ 3.0 3.1 3.2 3.3 Adam Lee, Christopher Perkins (September 17, 2019). Baldur's Gate: Descent into Avernus. (Wizards of the Coast), p. 200. ISBN 0786966769.