So, earlier today I figured that I'd take on Atlach-Leng, solo of course, since groups take forever to find, and I did the first minions just fine. (Take in mind that this is my second time in here), and then I got on the boss himself. I read on central that if you leave one of the minions alive, then he won't summon more. So I giant, and leave one of the minions with 170 health. A couple (actually I have no idea) turns later, he summons another minion. This made me a little upset, since central was off. But a few turns latter I defeat the boss. So, I only had like 500 health, and two minions are alive. I heal for 300 (with a Satyr, a Doom and Gloom and an Infection), and die maybe two turns later.
Now, that all made me upset. But what was worse was that afterwords I went back. The first battle-dudes were gone, but there was only one of Atlach-Leng's minions. This would have been fine, good even, expect that for the quest I still needed to collect the Moon Tear from Atlach-Leng, and there was none.
AND YES- I know that if I go back in, it all reset and be all fine and dandy. BUT I do believe its a glitch and needs fixing, and a frustrating one at that.
Update: I did manage to defeat this boss, the key is too go after the boss first. This was very frustrating, however, and still deserves some attention.
