Gaia is a huge monk-like warrior, who was once an elite member of the Secret Society; a criminal organization that sponsored the Toshinden tournaments. Gaia&#039;s wife Kaede, who was once the &quot;Uranus&quot; of the group, was killed in a car crash and Gaia suspected that the woman who was destined to be the next Uranus was behind the crime. Determined to seek vengeance against the new Uranus, Gaia had held the first Toshinden tournament behind the back of the Secret Society in an attempt to start a rebellion. However, when Uranus learned that he had held the first tournament without the approval of the organization, she branded him a traitor and marked him for death. However, Gaia escaped and went into hiding.  One year later, Gaia had received an invitation to participate in the second tournament. He reunited with his long-lost daughter Ellis and entered the tournament with her, hoping to get revenge on Uranus. At the end of the tournament, they were successful in destroying her and the Secret Society with the other fighters. However, Gaia had then discovered that he was being targeted by the Organization, a long-time rival group of the Secret Society. He entered the tournament hosted by the Organization with Ellis, in order to help bring it down. Gaia&#039;s whereabouts after the events of Toshinden 3 is never explained, but it is likely that he may have reconciled with his daughter Ellis before his departure and he told her that he would always be there for her.

For one year, Master Swordsman Eiji Shinjo has been haunted by the memory of his battle with the renegade champion, Gaia - a battle that was cut short by the forces of the malevolent syndicate known as "the organization." 
Denied victory, Eiji left the tournament followed by his opponents mocking laughter. Worse still, Eiji walked away no closer to finding his long lost brother, Sho. But now, a mysterious warrior is hunting down the champions of the previous tournament and using their own moves against them - and it looks like that person may be Sho. Who is this powerful new foe and who is his next target? 
Eiji and Kayin, his closest friend and greatest rival, struggle to unravel the mystery before they, too, join the ranks of the defeated. The answer lies at the heart of the Organization and its plans for world domination. At last, the ultimate battle between the greatest fighters in the world will be decided. But if Eiji loses, his friends - Ellis - may Die... 
(Source: AniDB)

Non-anime roles:
~!Abobo in "Double Dragon" (Neo-Geo) (VG)
Andorf (Andross) in "Star Fox 64" (VG) (Japanese)
Ashuraman in "Kinnikuman Generations" (VG) (Japanese)
Ashuraman in "Kinnikuman Muscle Generations" (VG) (Japanese)
Ashuraman in "Kinnikuman Muscle Grand Prix 2" (VG) (Japanese)
Ashuraman in "Kinnikuman Muscle Grand Prix MAX" (VG) (Japanese)
Ashuraman in "Kinnikuman Muscle Grand Prix" (VG) (Japanese)
Baloo in "The Jungle Book" (Disney animated movie) (Japanese)
Baron Praxis in "Jak II Renegade" (VG) (Japanese)
Bass Armstrong in "Dead or Alive 2 Ultimate" (VG) (Japanese)
Bass Armstrong in "Dead or Alive 2" (VG) (Japanese)
Bass Armstrong in "Dead or Alive 3" (VG) (Japanese)
Bass Armstrong in "Dead or Alive" (VG) (Japanese)
Black Hole in "Kinnikuman Generations" (VG) (Japanese)
Black Hole in "Kinnikuman Muscle Generations" (VG) (Japanese)
Black Hole in "Kinnikuman Muscle Grand Prix 2" (VG) (Japanese)
Black Hole in "Kinnikuman Muscle Grand Prix MAX" (VG) (Japanese)
Borgan in "Lunar 2: Eternal Blue" (VG) (Japanese)
Burnov in "Double Dragon" (Neo-Geo) (VG)
Cobra Bubbles in "Lilo & Stitch" (Japanese)
Dai Maoh in "Super Dodge Ball" (Neo-Geo) (Japanese)
Demon Knight in "Dragon Quest" (drama audio)
Edge Master in "Soul Calibur" (VG)
Elvis in "WILD ARMS the Vth Vanguard" (VG) (Japanese)
General Pepper in "Star Fox 64" (VG) (Japanese)
Gilgamesh in "Final Fantasy XII" (VG)
Heihachi Mishima in "Death by Degrees" (VG) (Japanese)
Heihachi Mishima in "Namco X Capcom" (Japanese)
Heihachi Mishima in "Soul Calibur 2" (VG) (Japanese)
Heihachi Mishima in "Tekken 4" (VG) (Japanese)
Heihachi Mishima in "Tekken 5" (VG) (Japanese)
Hoslow in "Emerald Dragon" (Drama CD) (Japanese)
Illgoga in "Tobal No. 1" (VG) (Japanese)
Jack Mathers in "Time Crisis 4" (VG) (Japanese)
Jirado in "Astal" (Sega Saturn Game)
Lazarus in "Shining Tears" (VG) (Japanese)
Lord Zedd in "Mighty Morphin Power Rangers: The Movie" (live-action movie) (Japanese)
Master in "Xenosaga Episode II: Jenseits von Gut und Bose" (VG) (Japanese)
Mike Bison [Balrog] in "Street Fighter II Made Revenger" (drama audio) (Japanese)
Mr.Satan in "Dragon Ball Z Ultimate Battle 22" (VG) (Japanese)
Mr.Satan in "Dragon Ball Z: Budokai" (VG) (Japanese)
Mr.Satan in "Dragon Ball Z: Sparking!" (VG) (Japanese)
Orson Perrault in "Ace Combat 5: The Unsung War" (VG) (Japanese)
Pigma Dengar in "Star Fox 64" (VG) (Japanese)
Pigma Dengar in "Star Fox Assault" (VG) (Japanese)
Robin Mask in "Kinnikuman Muscle Grand Prix 2" (VG) (Japanese)
Robin Mask in "Kinnikuman Muscle Grand Prix MAX" (VG) (Japanese)
Robin Mask in "Kinnikuman Muscle Grand Prix" (VG) (Japanese)
Robin Mask in "Kinnikuman Nisei: New Generation Choujins vs. Legend Choujins" (VG) (Japanese)
Robin Mask/Barracuda in "Kinnikuman Generations" (VG) (Japanese)
Robin Mask/Barracuda in "Kinnikuman Muscle Generations" (VG) (Japanese)
Scott Dolph in "Metal Gear Solid 2: Sons of Liberty" (VG) (Japanese)
Shingen Takeda in "Samurai Warriors" (VG) (Japanese)
Shingen Takeda in "Samurai Warriors: Xtreme Legends" (VG) (Japanese)
Sigurd Sidmeyer in "Galaxy Angel Moonlit Lovers" (VG) (Japanese)
Taira no Kiyomori in "Genji: Dawn of the Samurai" (VG)(Japanese)
Uighur in "Hokuto no Ken: Seikimatsu kyûseishu densetsu" (VG)
Vargas in "Der Langrisser" (VG) (Japanese)
Volf in "Ninja Gaiden Sigma 2" (VG) (Japanese)
Volt Krueger in "The Bouncer" (VG) (Japanese)
VSSE Director in "Time Crisis 4" (VG) (Japanese)
WRO Fukuchou in "Dirge of Cerberus: Final Fantasy VII" (VG) (Japanese)
Yosemite Sam in "Looney Tunes" (Japanese)
Yosemite Sam in "Space Jam" (Japanese)
Zappa in "Poporogue" (VG) (Japanese)
Zou-Daimaoh in "Puyo Puyo" (PC Engine CD-ROM²) (Japanese)!~

Based of the Playstation Game Battle Arena Toshinden 2.
 
Note: Released in Enix Supercomic Gekijoh Volume 1.