Taslan the Devourer

Taslan the devourer is an elite purple spider found in the northern ruins. She is the 1st of two bosses you have to defeat in the area. The brood-mother has two younger spiders to help her fight. she is tamable with a shadowbind tome which can be obtained in the auction house for around a gold or by killing braghin shamans in the nearby braghin war camp

From the Bestiary
"A dark magic lurks in parts of the Brakarr Forest, and the great spider Taslan is proof.

The spiders of Brakarr are enormous, dangerous, and best avoided entirely, and Taslan is the most dangerous. Some travelers have reported seeing figures in black interacting with her - vile Khabimists, most likely.

And yet, in spite of these warnings, Taslan shows the potential to be a hardy mount.

Given the Khabimists' ability to walk among Taslan and her brood, it is speculated that their magic can tame the savage beast. An adventurer who obtained one of their Shadowbind Tombs might make her their familiar."