I've seen this Giant Bat in Trynton with every party( 4 parties so far). It NEVER attacked though. One time it was close enough for my bow/slingers to target it but it ran away during the first round. In this current game I hit it with a Fireball to force it into attacking me. The fight was a bit tough but fun. Didn't give much experience though. I suspect this was part of an additional Trynton quest that was never fleshed out. Poor Trynnies. Breeder Ratts, the Rapax, the stigma associated with helping Marten, and to top it all off, a Giant Bat who steals their babies( just an idea for the unfinished Giant Bat quest)
Spence