Copper level, week 5. Overlord has used 30 conquest (xp) to upgrade beasts to silver.
We ran into the following in an RTL dungeon. On the overlord's turn, he plays the crushing blow on hero Zyla and destroys her weapon. It is now the hero's turn. One of the heros runs, opens the rune door, and escapes into the portal. Two other heros follow suit (3 are off the board via the portal and cannot come back).
The fourth hero (who is Zyla with the fly ability and only worth 1 conquest token if killed, and with no weapon), decides to remain in the dungeon for 1 extra turn to gather up 2 Coin tokens (worth 800 coins to the heros). The heros felt that the trade off of 800 coins for 1 conquest token if Zyla as killed was acceptable. She has enough speed to run and gather both coins, but cannot get out the portal on that same turn.
On the overlord's turn, he spawns a silver naga in such a position, that allows him to get next to Zyla. Zyla is grappled, with no weapon. She can only roll a red dice for a fist attack (max damage 4). Since the naga is a 4 armor, 14 health beast, Zyla can do no damage to him.
The overlord makes no attempt to kill Zyla, and ends up burning through his deck, resulting in 3 additional conquest. The overlord eventually does this a second time, earning 3 additional conquest. At this point, the heroes are forced to flee, and thus return to Tamalir.
As one can imagine, this resulted in some heated debate. It was the hero's choice to run the risk to get the additional coins. The overlord did nothing against the general rules. Several of us, who participate on this forum, believe we had read somewhere a general ruling that the overlord can not create unsolvable situations in a dungeon (such as creating an impassable cooridor, or something similar).
The question we have is as follows: Are the actions of the overlord, while following the strict letter of the rules, actually permitted? Or does the overlord need to make a good faith effort to kill the remaining hero?