The first time I played SoA, I just walked into thé guarded compound in temple district and killed the monsters and grabbed the all the good stuff in there. Though I am woundering if it is part of a quest and if it is, what will trigger it?

Nothing. Its just a fun fight for XP and lots of treasure.

it WAS part of a quest, but time or budget or disc capacity ran out and it was never finished. apparently it would have been conected to the Twisted Rune and the slaver stockade.

I would suspect the slaver stockade, cuz they are called the Slave Lords. And thats why they made the empty potion bottles appear, which now have NO use what so ever.