Sol is one of the best characters of the game. His attack power and defense are good, but he is somewhat slow. If facing a fast character, play it defensive. Everything else about his is average. He's your typical Ryu character.

Moves List

Gun Flame - QCF+P
Volcanic Viper - DPM+S or HS (OK in air)
Volcanic Viper Addition - QCB+K during Volcanic Viper (OK in air)
Grand Viper - QCB+S (Ram the buttons rapidly for more hits on the slide)
Bandit Revolver - QCF+K (OK in air)
Bandit Revolver Flame End - Hold K after in putting Bandit Revolver
Riot Stamp - QCB+K
Wild Throw - DPM+K (close)

Overdrive Attacks

Dragon Install - QCBx2+S - This turns the HS Volcanic Viper into a super. It also makes Sol the fastest character in the game. After it wears off, Sol will be vulnerable for about 2 seconds.
Tyrant Rave - HCB,F+HS

Instant Kill

Press All 4 Buttons to activate the "Attack Mode" then while in it:
Napalm Death - QCFx2+HS

Combos

P, K, S, HS, Tyrant Rave
This is a basic gatling combo for Sol. Just follow what it says and you should pull it off.

Guilty Gear Mode Changes

Sol's Bandit Revolver flame end becomes bigger and hits for more damage and combo wise.

Gold Form Changes

Regens, always in Dragon Install.