|Title||The Ultimate Organism|
OverLord GAIA is a Master Computer Digimon that was the final boss in Digimon World 2. He has the capability to act, speak, think and plan by himself, and basically any intelligent trait a human has, he will exceed. He is very malicious and ruthless, using humans only as test subjects in his evil intentions (although he does it from behind the scenes, so the humans are not aware of their position in GAIA's experiment).
OverLord GAIA was created from the GAIA Project, directed by Chief Carol, who was the operator at the Main Gate of Digital City. The central computer GAIA started to evolve on it's own, and later took over the entire project and trapped everyone inside the Digital World. No one could escape as long as he was the operator of the Digital World. OverLord GAIA likes to call himself the Ultimate Organism. He is the secret ruler of Digital World, known to Digimon only as a "god".
OverLord GAIA has six energy cannons mounted on his back. They have extremely high firepower, and they can be switched to use live energy or amplified storage energy. The cannons are energized by and connected in the metallic core in OverLord GAIA's back. He has a wide lower torso, possibly due to the kick the cannons may provide. Inside of OverLord GAIA's mask lies a red wireframed person whose face seems very beastly indeed. He also has three glowing red eyes, although the third eye looks more like just a decoration light before it is actually shown in the ending FMV of Digimon World 2. One of OverLord GAIA's most notable tricks is that he can actually detach his arms and switch them into Auto-Attack mode, essentially making himself three times more powerful in the process.
OverLord GAIA controlled the events of the Digital World from the top of Chaos Tower in Kernel Zone. He came in contact with and took control of Crimson, who was a high-ranking Guard Tamer. Crimson fell victim to GAIA's evil and became the leader of the infamous revolutionaries, the Blood Knights. GAIA also came in contact with a strong will on File Island, and dominated their mind too. The mysterious strong will was turned into the Prince of Evil, ChaosLord. In addition, when GAIA's plan took a great spurt towards completion, his evil also started to haunt the minds of those in Meditation Dome; which is, ironically, the place where Digimon would go to meditate and calm their minds to prevent losing it.
If OverLord GAIA was ever going to be defeated, he would make sure to take the entire Digital World with him, as proven when Akira in fact defeated him. However, this act was foiled by Esteena, who managed to transport herself to the Digital World after finding out what OverLord GAIA had done to the personnel of the GAIA Project. She then managed to go back to the real world with Kim's little robot, which was coincidentally also named GAIA. After she asked it a question concerning the GAIA backup program, the little robot began to read the backup, claiming it to still be operational. Esteena and the little GAIA disappeared in a flash, just in time to arrive at the real world to enable the backup program that would save the people trapped in a self-terminating Digital World that no longer had an operator to run under.
OverLord GAIA planned to defeat Akira, the strongest tamer, and combine with him to become an almighty, true god-like being. After that, he would simply reach out to every Digimon and make them start a war. More than that, his ultimate objective was to become the god of both the Digital and the Real World, although it remained clouded in mystery how exactly he would achieve that from a war in the Digital World. It is possible though that merging with Akira would have enabled him to influence the events in the real world as well.
When Akira confronted the titanium Overlord at the 20th floor of Chaos Tower, GAIA revealed that Akira had been nothing but a stage of his experiment; Akira had previously defeated GAIA's "Chaos series Digimon", who are none other than the Chaos Generals and ChaosLord. GAIA noted that Akira had also defeated the test combination of the chaos series Digimon and Crimson (Matrix ID 04XY), which means NeoCrimson. By now, Akira had become the strongest tamer, and OverLord GAIA would merge with him to reach a stage of power no other being could possibly have. However, Akira refused, and GAIA decided to initiate his fighting program.
Eventually, Akira turned out to be stronger. OverLord GAIA was beaten back, although he was still more than capable of fighting. He detached his arms and retaliated, channeling his amplified storage energy to dramatically improve the power of his attacks. Akira was given a challenge of destiny, but eventually he found his strategy to defeat the malicious god. OverLord GAIA was so severely damaged that the cannons on his back completely fell apart to the ground. He himself got up though, and activated a self-destruct sequence and left a massive explosion of green energy behind, wiping Chaos Tower out. If it wasn't for the previously activated backup program, the Digital World would have been reduced into nothingness along with its ruler, OverLord GAIA.
 Battle Data
- Initial Form
- HP: 432
- MP: 432
- Attack: ???
- Defense: ???
- Speed: ???
- Second Form
- HP: 648
- MP: Unknown (presumably 648)
- Attack: Unknown
- Defense: Unknown
- Speed: Unknown
- The floating arms both have 270 HP.
- Form 1 Techniques (attached arms)
- Titan Laser (Glory Weapon) - Laser shot on all enemies
- GAIA Gear (God Punish) - Good only in counter-attack
- Fantasmic Bomb (Phantom Screen) - Attack wave on all enemies
- Form 2 Techniques (detached arms)
- Fantasmic Ray (Phantasma Wall) - Devastating attack wave on all enemies
- Tubular Attack (Cylinder Flail) - Counter-Attack hits all enemies strong
- Light Gun (Last Gun) - Shoots stored Light energy
- Left Hand techniques
- Left Hand (God Hand Left) - Gives foe a backhand slap
- Reduction Ray (Infant Ray) - Lowers an enemy's attack power
- Right Hand techniques
- Right Hand (God Hand Right) - Gives foe a backhand slap
- Destablizer Ray (Land Disruption) - Lowers the defenses of all enemies
- OverLord GAIA calls himself the "Ultimate Organism", but organism is in fact an erroneous term, seeing as he is a master computer Digimon with every aspect being mechanic.
- The technique, Light Gun has a more literal translation being Last Gun. Both actually describe the technique very well; it really looks like it uses some kind of light energy, and OverLord GAIA always uses it as a last resort technique after his arms have been defeated.
- Even though OverLord GAIA's face may give out an imagination that his voice would be very sneaky and hysteric, his actual voice-over, when using a technique in battle, is a combination of very steely and manly vocals, giving a player the feeling of his true wrath.
- In the ending FMV, it is shown that the Chaos Tower is in fact a living object, and it imitates whatever OverLord GAIA is doing. This is strongly suggested when OverLord GAIA's red eyes suddenly turn into real eyes and the Tower's single eye transforms as well, just before closing itself. There are streams of data falling down like tears from the tower's eye. Also, when OverLord GAIA lifts his arms high in the air, the tower also raises some kind of poles from itself and undergoes some random metamorphosis.
- Fantasmic Bomb and Fantasmic Ray have unusual text when they are used. Before the attack's name is shown, it displays a small text that says "Unknown Attack".