About seymour guado, lease answer my questions

why exactly did he want to end spira of its 'sorrow', what was the reason

did he descend into insanity after his traumatic childhood or did he merely think about and wanted the best for spira/

did he actually have a bit of feelings for yuna, because some evidence for example was that when he kissed her, he looked pretty nervous another ex would be he asked yuna to marry him as well as throwing a lavish wedding ceremony when he could've made it suck as well as treating her kindly, even after she found out about his father, he'd address her formally as well as saying something like how he was glad to see her

was he trying to do what he believed was right or was it because he simply wanted to like other villains such as sephiroth or kefka

last thing is so was seymour in a way a tragic hero

To me, Seymour was just nuts, nothing else. Nothing, absolutely nothing made me see even a bit of good in him, he was a total nutcase from the start (or at least from the moment he entered to the storyline).

...okay, the Summoning at the Blitz Arena was pretty cool but otherwise all the things point that Seymour had a twisted mind because of his Guado/human lineage - and his way of saving the people of Spira is through death, that all the life dies on Spira, so Sin wouldn't be of a burden anymore to anyone. It's a noble thing to believe so, but very cruel and not very heroic IMO. And when he becomes an unsent, his views are strengthened by that and he just kills people mercilessly who get in his way.

did he descend into insanity after his traumatic childhood or did he merely think about and wanted the best for spira/

Well, to put it simply, he was a Guado/human hybrid, who was exiled to Baaj as a child with his human mother, where his mother turned into a fayth so that Seymour could defeat Sin and be accepted in the Guado and human societies. But when his mother died, he became insane.

And with the marriage with Yuna, he would gain political power within Spira, their marriage would boost Seymour's support within Spira and he would be seen as a saint, of a kind. I think it was just for that he could operate in the shadows to destroy Spira.

IMO, Seymour was just a lunatic who had a bad time as a child. :3

Seymour was a dick, never liked him.

He wanted to end spira of its "sorrow", which was Sin, because he believed that as long as Spira existed it's people would suffer because of Sin. e he believed that as long as Spira existed it's people would suffer because of Sin. Destroying Spira wouldn't rid the world of Sin, but the people would no longer suffer...because they'd be dead I guess.

Regarding Yuna, I believe he did love her, but he was already dead by that point and well he was just a creep.

He was the antagonist of the game, had considerable influence over Spira, was an asshole.

"Though Seymour appears courteous and affable on the outside, this is merely a front to hide his sinister motives, and when called upon he drops the pretenses and reveals his true nature as an arrogant and cruel man."

He really couldn't do much Yuna in his state so I'm not sure about that. As for the others he thought if as long as it existed sin would be around.