The renegade Ger is attacking the town (from DL3?)

[Brysos]

My town was under attack by Ger. I ran around fruitlessly trying to find him, as he set traps, cursed and petrified people. Finally I went to talk to the warmaster and he gave me a quest to kill Ger on dungeon level 3.

This is the first time I have had a being attacked by a monster who is not actually in the town! Is this intended behavior?