Cloak of Shadows

Cloak of Shadows is a novel by Ed Greenwood and the second book in The Shadow of the Avatar Trilogy.

Synopsis
"The Time of Troubles had arrived. The chaos of spilled blood, lawless strife, monsters unleashed, and avatars roaming Faerûn had come.

But wrathful and warring gods were not Faerûn's only problem.

The dreaded and insidious Shadowmasters had seized the opportunity to increase their influence and power while Mystra and her minions were otherwise engaged. The Shadowmasters had woven a magical cloak of spells that would render the wearer invisible to their rival's magic.

The shadow over Faerûn spreads."

- Amazon.com