A glance at the guide Dissecting Thrall, the Far Seer:
Thrall is best laned with a stunner or a slower that has a high DPS potential early in the game; however, the power of Thrall is best utilized when his lanemate's stun/slow is targetable. Combining a high-damage nuke with abilities that prevent the target from escaping, the Far Seer is the perfect lanemate for quite a large number of heroes.
Full guide can be found here.
Links
Dissecting Thrall, the Far Seer - Full Guide
