Sorry, but that still doesn't really work. The rebellion wasn't organized by a single person; it was the result of a number of independent rebellions joining together. There was also no release of magic from the destruction of the Dweomerheart. The thing that devastated the planet was the sorcerer-king's battle against the abomination, which lasted a few days and raged across Earth. The abomination couldn't have been summoned by a few guys that panicked; it was a carefully coordinated ritual by a large number of mages when all else was hopeless. Something like that couldn't have been done without planning.

You seem to be trying to set up your character as the sorcerer-king's arch-nemesis and the person most pivotal in his downfall. I can't allow that. The sorcerer-king was brought down by the collective will of all the people he oppressed, not any single individual; his actions and the consequences of said actions were global rather than personal in scale. At most, I can let your character be [i]one[/i] of the leaders of the rebellion, possibly one that was against summoning the abomination. No personal rivalry with the sorcerer-king.