Quote Originally Posted by Aurons Ghost

To an extent yes, but he may lose control one day, Sin's will may be too strong to permentantly resist, and Yevon can only allow himself brief periods of control to prevent sin from destroying something, like the Dream, or the Fayth.
I dun think Sin has any will...since it is a shell, and the core make it destructive.

This brings me to a question about what is Sins true nature. To bring death and destruction as Yevon and the Fayth claim, or did Yu Yevon have some other purpose in mind for Sin,
I believed that Sin will just keep on destroying stuff and continue the Spiral of Death because it had lasted for 1000 years already, so if it had something purpose in mind, maybe it should have done so it earlier.

eg only attack places where the people might become developed enough to destroy the Fayth or even find the physical manifestation of the Dream?
The people wouldn't become developed if the Yevon Church control them which is why Yunalesca strike a deal with them.