The latest developer video for the MMO installation in the Elder Scrolls series, Elder Scrolls Online explains the setting of the MMO world.
In particular, this video details the history behind the power struggles between the three alliances, Daggerfall Covenant, Ebonheart Pact and Aldmeri Dominion, all seeking claims to the “fertile heartland of the continent” that is Cyrodill, which is essentially a power symbol. The Tharns ruling Cyrodill, on the other hand, feel the threat of the alliances as they feel they are losing control of their position.
The three alliances have their own motivations to take control of the continent. The Daggerfall Covenant ruled by the Bretton High King Emric feels entitled to rule instead of the elves. The Ebonheart Pact has a more mystical motivation for their cause; they feel that the continent is in danger, and they are the ones who can cleanse it.
The Aldmiri Dominion ruled by Queen Ayrenn has a more personal and emotional motivation as they feel that the humans have shed too much blood and it is time for the elves to take over the white gold tower which “they built in the first place.”
This history behind the alliances and their goals adds a deep story and gameplay element to the world. The players get to experience these forces at work and get to look at the region through all three vantage points.