Transylvito who seem to have a talent for employing them and may be a sole user.
Doombats, under the command of Count Vinny Doombats, are one type of flying unit included in Prince Ansom's coalition against Stanley. Doombats are relatively weak in combat. However, they are very useful for scouting: Vinny can remotely look through the eyes his doombats. It appears to cause Vinny distress to "watch" while one of the bats is croaked in combat.
A scouting bat discovered the incoming raids against Ansom's siege units, and additional bats mapped out a ring of dwagons that had apparently been deployed as a defensive formation for the wounded raiders. In each case, the bat was lost after encountering the enemy, being no match for a dwagon.
After a force of forest units led by Ansom broke into the dwagon ring, a bat was sent into the protected center hex of the ring, and found it to be empty. Ansom did not consider this finding to be final, and went to see for himself. Wanda Firebaugh speculated that he believed that the center hex contained veiled units. These events indicate one limitation on doombats' scouting ability (they are apparently more susceptible to deception by veiling than a high-level warlord such as Ansom).