I know this is asking for a spoiler, however, let me explain:

So far, I've avoided the main game quest line. I know, I know, you're supposed to be concerned over the whereabouts of your sister, but I'm thinking that, to start that with a wimpy character is just not same.

So, in my travels, someone told me the story of Aziraal and the Orcs; a prophesied battle where only the best warriors in history fight evil, but the Orcs can't participate because they have no souls. They are trying to get Aziraal reborn so he can possibly have the ability to give them souls, so they can fight in this battle. They believe that, if they don't fight in this battle, it will be lost.

At least, that's what I've gathered so far.

Now, my questions are: What if you decide to help the Orcs, and release Aziraal? Can you become friends with the Orcs? Can you save your sister, help the Orcs, and still thwart her kidnappers? If you do help the Orcs, are you dooming the rest of the human race? Has anyone tried this (I find no reference on web searches to joining the Orc's cause)?

Edit: (Sorry for the extra "Q:", this was my first message posted as a question, I did not know it automatically added that if marked as a question.)

As far as I am aware from my own playthrough, the only two missions that actually benefit the orcs involve giving their human agent near Cathalon the catapult triggers (which is optional) and allowing them to storm into Ashos by stealing the eye of Yatholen from the temple (which is unfortunately part of the main quest).

Yeah, I think anvilsmith is correct. I got the sense that the developers wanted to give the player more options to side with the orcs but it ended up not really being implemented.

There are opportunities to side with the Necromancers, however. Their conflict with the mages is kind of similar to the conflict between the orcs and humans, in that it's not really clear which side is in the right.