Evry vill throught f history was desent in his/her own way. ill name a few ways

(SPOILER)ff4/ zemus was screwing ppls lives for years by temptation leading to mind controle.
ff6/ kefka was a friggen lunatic (NOF SAID)
ff7/ sephy was so misunderstood and he took his ****ed up life to the extreme
ff8/ (forgot name for some reason) she took controle of rinoa and edeas minds by linking to there powers.
ff9/ kuja wanted revenge towards his father and to wipe out his whole race.
ff10/ seymour, in my oppenion is the most misunderstood, if tidus and co wouod have butted out and let yuna marry the guy then all would be ok. (then just kill him wile he sleeps lol)
ffx-2/ shuyin wanted to bring back the love of his life and was heartbroken when yuna wasn't her. as was yuna when he wasn't tidus.