<font color = shadowed cyan> I cant seem to find the last chain i need to continue further into undermountain, I have all of them except the yellow one. I have chacked all the off shoot levels and stuff but I cant seem to find it anywhere. Help please.</font>

There's a chain on the corpse of the goblin you see getting slain by drow when you enter the level. Just a thought since I've missed that one in the past!

Lets see, yes, one on the goblin at the start; One in the room where the drow are camping (In the chest or on the commander); One with the Rakshasas leader; and one more on the goblin leader. Speaking of him, what did those three levers do again.

Of course the real fun is triggering the chains properly once you have them set.

Yeah that was a riot, it took me like 6 or more times to finally get it...