I dont understand the end of Assassin's Creed 2

Fact 1: Desmond Miles is a descendant of both Altaïr ibn La-Ahad and Ezio Auditore da Firenze.

Fact 2: Abstergo Corporation is exploiting Desmond Miles to go back in his genetic memories.

Question: What is the goal of Abstergo Corp., what benefit do they wish to make, by investing billions of $ in that project?

[spoiler] They're looking for the pieces of Eden. If they have all of them then they basically control the world. Somewhere in Desmond's family past is the key to finding them all. [/spoiler]

yes, desmond is descendant from both ezio and altair, if you unlocked the truth video combined with the ending you realize that long ago humans were enslaved by some aliens or "gods" using the pieces of eden, adan and eve the first assasins so to speak stole one of the pieces of eden "the apple" and started a war with them to free manind, the gods were more advanced but humans were a lot more, in the middle of the fight a disaster happened, something related to the sun i guess killing most of the life on earth, and is going to happen in 2012 again but the gods created a device that can prevent this from happening (i think this is what desmond will have to look for in ac 3) abstergo which are the modern time templars who have always been at war with the assasins have always been looking for the pieces of eden because they know with them they can rule the world but they don't have any idea whats going to happen with the sun, and problem is they are close to getting all the pieces and enslaving humanity