If you do the quests, you will know.

Why don't you enlighten the rest of us then? You know, the ones that did every quest and still don't understand why one section contains Ethereals while another contains the Shadow Council and another contains Arakkoa. Each seemingly having nothing to do with one another and exist solely as loot-pinatas. Where's the overarching story as to why these different groups exist there in the first place?

Auchindoun itself was a Draenei temple city of the dead that was considered a very holy site. At one point it got overrun by the Shadow Council who practiced their variety of bad mojo there and ended up summoning an elemental lord that destroyed the joint. So now it's kind of a magical hot spot and all the instances there represent the various factions that are fighting for control of the place.

The story behind Crypts specifically is the priests there are traitors who serve the Legion, and they're raising the dead there to serve them. The ethereals are in Mana Tombs because the explosion that destroyed Auchindoun tore a rift in the Nether that drew them there, and they're ransacking the place for magic shinies. SLabs is where the remnants of the Shadow Council are trying to control the elemental Murmur and take over the place again. And Sethekk is filled with crazy bird dudes using the energy of the place to practice bad mojo.

http://www.wowwiki.com/Auchindoun

Read that.

If you do all the quests involved in the instances, you will get the overall picture of why they are there. They don't have to be connected to be there. There is no real connection between the Arakkoa and the Ethereals being there, but the instances are big enuf to support multiple factions. To give a slightly flawed example, in Gnomer you have four forces. Irridiated Gnomes who think you are Troggs, and thus attack you. Troggs, which are aligned with Thermplugg, Dark Iron Dwarves, which are aligned with Thermaplugg, and Thermaplugg himself. Now while three of the four fit the instance, they are not together. The Gnomes only attack you because they were irridiated, and are trying to defend their city.

Each wing has a different faction in it for a different reason. Each of the reasons make sense. They don't all have to mesh together.

@Drakkenfyre: It's really no different than the classic D&D settings, where you have giant ancient ruins and various groups of people picking through them with their own agendas. Myth Drannor in old school Forgotten Realms comes to mind.

Auchindoun actually has some damned interesting history behind it, it's one of the more interesting places in BC, IMO, and goes a long way toward dispelling that widely held misconception that the Draenei are just boring white hats.

"...SLabs..."

You did that on purpose now, didn't you? No, I will NOT say that it SHOULD be called Slab, since it's a labyrinth, and not laboratories. No, I will not do that, I am over it.

always been "slabs" to me... I actually forgot it wasn't a laboratory until I read your comment...

I think I have been calling it "Shadow Labs" in real life since halfway through BC.

oh man i miss auchindoun. those dungeons were fkin hard, and even when outgearing that place you could still wipe. dam i miss the possibility of death in a 5man.

sheeping, and sapping, and stunning, and interrupting, and killing skull first.
good times, good times.