A popular fan genderswap of Ky Kiske, who is like the Ken to the Ryu of Sol Badguy (only because Guilty Gear is for Chads, they play nothing alike whatsoever - they're both quite simple to play by GG standards though.)
Sol was one of the scientists who created the Gears in the first place, using himself as a test subject - successfully. He's immortal and a few hundred years old, so he's had time to get very disillusioned. Ky is just an extremely skilled Knight who fought alongside Sol in the Holy War against the gears, eventually becoming King after humanity's victory.
Sol left the Order over inevitable ideological differences - he'd only been there to try and correct his mistake in the first place and never liked their lawful methods.
This is why Ky has "HOPE" scratched into his belt, but Sol has "FREE."
The loli I posted is Dizzy, Sol's gear daughter. Ky actually ends up marrying her and having a son, Sin Kiske..... Who drifts away from his father and becomes the protégé of his grandfather, Sol.
Guilty Gear family trees are as confusing as ours.