Ranks

Alpha / King
There is usually a Male and Female in a pack but in a Kingdom there is usually only one because the mate of the King will leave him because they believe that the power had gone to their heads. They have the most power in the pack.

Alternative Alphas / Betas
These are usually highly loyal and committed males but if they have mates then they take the rank too. Also, this rank is mostly given to the offspring of the Alphas. If the Alpha leaves or dies then either the offspring or oldest Beta will take over.

Subordinates
This is the bulk of the pack, they follow orders from the Betas and Alphas.

Omegas / Slaves
This rank is at the very bottom and are treated like nothing. They are the most abused both sexually and physically, even pups use them as practice hunting and torture toys.

[From the Terms section]

Slaves are a key aspect in a Starpack pack, they are like Omegas only they can't be pushed around as must as they serve the Alphas and Betas. Slaves are usually abandoned pups that a Starpack pack has found and raised as slaves. Pups can start their work as early as when their eyes first open. Slaves never have contact with the outside world with the exception of hunting, they are not allowed to go hunt with the rest of the pack, they are not allowed to leave the pack, they are not allowed to play and they are not allowed to eat the prey they hunt. All the prey they catch go to the Alphas and Betas, what's left over is for the slaves. Slaves usually live in isolated dens, away from the other wolves, they sleep alone; they are not allowed to sleep with other slaves. Some of the good things of being a slave is that if you're ill the medicine wolfs will help you and you are given a sign of importance (because the Alphas can't live without their slaves to do everything for them.)

Slaves don't get the choice, they are forced to be Starpack wolves.