[Saxon]

The Visitor, with something like 10 strategic movement is a thug that you can drop anywhere in a hurry. Combined with intelligence from spys, assassins and astral windows, it can be very useful.

Especially if your opponents is trying to get into the water with you and can not buy PD. Let them come in a bit, then cut off their escape with the Visitor, at the same time, hitting their main army and forcing it to retreat.

Or hitting lake provinces in the middle of your land based opponent. Throw up some PD and a temple. Perhaps a castle and a raiding force.