A question about the very beginning of this game

[L9999]

First of all, HI THERE NICE PEOPLE OF THESE FORUMS! This is my first post~ ahaha...ahem. yes.
It's kind of a lame first post because I am re-posting it from somwhere else where it didn't get any answer, I hope that's not rude... I promise I'll never do it again. I'm just very very very curious about it, and I'd like to know what people around here think about this thing. Yessss.

So here goes: why the heck does Sin attack Dream Zanarkand, when we just start this game up, if Sin was created as a SHIELD to protect Yevon so he could SUMMON Dream Zanarkand? Is this ever explained and I'm just forgetting it all like the idiot I am?
Because seriously. What's the point in that? I mean, I get it, getting in touch with Tidus to transport him to Spira (1000 years in the future) so he could fight, yeah, but WHY destroy what you're summoning in the process? I mean how many Fayths did it take to make Dream Zanarkand? And not only that, the whole summoning of the city wiped off Yevon's mind (and no, that can't explain it getting insane and smashing it, because yes it wiped off its... human part, but it DID leave the /will to survive/, that what makes Sin recreate itself every time, and /protect Zanarkand/, that's what makes Sin fight and all) so why just go KABOOM on it?

[PuPu]

Hi and welcome to EoFF.

but WHY destroy what you're summoning in the process?

The Fayth didn't cause Sin to destroy everything. It was Jecht, who temporarily took control of Sin.

I mean how many Fayths did it take to make Dream Zanarkand?

The remaining Zanarkadians that didn't get killed in the war with Bevelle.

[L9999]

Hi and welcome to EoFF.

but WHY destroy what you're summoning in the process?

The Fayth didn't cause Sin to destroy everything. It was Jecht, who temporarily took control of Sin.

I mean how many Fayths did it take to make Dream Zanarkand?

The remaining Zanarkadians that didn't get killed in the war with Bevelle.

Oh, I see I see... so it was Jecht's remaining consciousness or something... yes, that does.... kind of make sense, yes. And he attacked DZ to get in touch with Tidus so he could have his son fight him himself. By the way, with "The Fayth" you mean Yevon, right? The one that lived at the time with the war with Bevelle and came up with the whole Dream Zanarkand idea...
Thank you for explaining it. That was bugging me a whole lot, ahah!

[PuPu]

Jecht's remaining consciousness or something... yes, that does.... kind of make sense

Yeah, cause Jecht is the Final Aeon that Yu Yevon morphed into Sin.

By the way, with "The Fayth" you mean Yevon, right?

No, the Fayth are the people that are on Mt. Gagazet (not the Ronso) and the various Aeon temples.

[Skyblade]

The way I view things, much of Sin's nature is instinctive. Sin's destructive nature is born of being overly protective, not out of a conscious desire to destroy everything, or any particular thing. Sin is Yu Yevon's armor. Anytime it detects something that might be a threat, it eliminates it, and it seems to deem all life (though not fiends, since fiends aren't alive) a threat.

The rest of its behaviour was likely based on the individual who became Sin. In this case, Jecht. Sin went to Dream Zanarkand because Jecht was reaching back towards home. Consciously or subconciously, we may not know for sure (though the fact he brought Auron would indicate at least some concious knowledge).

Jecht is Sin, for the most part. He's the one following Tidus around, the one who is moving from location to location. But he cannot control Sin's destructive nature. Anywhere he goes, no matter what he wants, he brings destruction.

This is why Seymour as Sin would be so dangerous. Every other individual who became Sin was a guardian, dedicated to protecting the world. While they couldn't control Sin's nature any more than Jecht could, they could mitigate it somewhat, keep Sin away from villages as much as possible, turn Sin away before everything is completely obliterated. If someone became Sin who would actively hunt out and exterminate villages, Spira would be doomed.