Tonight i just got done playing the quest hold the line in AoD and everything went well up until the end of the quest, turn 11 or so. We, the heros, had one glyph remaining and it was right next to one of the spawning areas for monsters. The quest guide says the quest is over once every master monster is killed and the overlord just spawned monsers in the area next to our glyph and we couldn't do anything because the quest book said that monsters can spawn here regardless of LoS. The monsters kept spawning there and soon our final glyph was destroyed, not to mention there were more and more master monsters we had to kill to end the game.
So my question is are we playing this quest wrong or did the overlord miss a rule? Now sure how you can beat this quest if the overlord can just keep spawning master monsters... And can you end your movement on a glyph to protect it from being hit?