Thrundarr's first quest is one of the most annoying ones in the game: you have to slay a random monster, and it can be either a very common or rare one. If it's rare, the player has to spend ages looking for it, before his remaining quests can be completed. Now that's just plain tedious and not fun. The quest shouldn't be that difficult considering the immediate reward isn't that great (literacy or complete inventory identification, both of which can be found elsewhere). Furthermore, the fact that the difficulty of the quest relies so much on luck doesn't make much sense from a game balance point of view.

My suggestion is to make it so that there's a limit on how rare a monster Thrundarr can order you to kill, so you never get TOO rare monsters.