Saki Amamiya (サキ・アマミヤ) is the main character from the game Sin and Punishment: Successor of the Earth. His main weapon of attack is the Cannon Sword, a gun/beam-sword hybrid which he uses to slash and shoot with.
Saki Amamiya made his first appearance in Sin and Punishment: Successor of the Earth. Alongside his companions Airan Jo and Achi, Saki is a member of the "Savior Group" that intends to take down a government agency in Japan called the "Armed Volunteers"; along the way, the group also has to protect civilians from the "Ruffians", a species of creatures that mutated from an genetically-modified alternative food source.
Throughout the game, Saki's weapon of choice, as well as Airan's, is the Cannon Sword. In addition to acting as a long-range firearm that can potentially lock onto enemies, Saki can also use the Cannon Sword to form an energy weapon that can slash enemies not unlike a sword. Through proper use of the weapon, he can also nullify some enemies projectiles. Saki himself is also physically fit, and is able to do flips and rolls while avoiding enemy fire.
Of particular note is that while Sin and Punishment was a Japan-only release, it featured voice acting that was fully in English, despite all of the text in the game being in Japanese. Brawl retains this by having Saki speak in English.
As an Assist Trophy
Upon appearing on stage, Saki uses his Cannon Sword to attack opponents. Depending on their location relative to him, Saki will either shoot straight ahead of him, or slash with his weapon in order to inflict damage; the shots have relatively little knockback and easily combo into each other, while the sword packs more knockback and can potentially KO at high percentages.
As to reference his agility in his source game, Saki is able to quickly run and jump all over the stage that he has been summoned on; while doing so, he can shoot his weapon while jumping, as well as immediately end his dashing to slash with his weapon some more.
As a trophy
Saki returns as an Assist Trophy.