The Ashta'daramai or Blue Djinn Fortress is located in the Kha'zeel (Ankrahmun Desert). This is where Gabel reinforces his troops to repel Malor and his Green Djinn and Efreets, hoping to eventually defeat them entirely and overcome the Mal'ouquah. The blue djinn are friendly towards humans, but remain reclusive and have limited dealings with them. Because of the war between the Marids and Efreets, they will not trade with anyone they do not trust entirely.
To reach the Ashta'daramai, simply follow the ramp into the mountains north of Ankrahmun (here). Be careful of Stone Golems that wander on that path. Also note that this hunting place is not very good for paladins (no space to outrun).
The Ashta'daramai is increasingly fortified when ascending the tower, with the highest floor having the hardest creatures.