Perfect Dark Gaia

Perfect Dark Gaia (パーフェクトダークガイア) is the final boss of Sonic Unleashed. It is the completed form of Dark Gaia which it assumes upon reaching its full maturity for the time of awakening, making this form the representation of Dark Gaia's true nature as a deity of darkness and destruction.

Dark Gaia assumed this form during its battle with Sonic the Hedgehog and the Gaia Colossus when it reached full maturity during the course of the battle, but was eventually defeated by the combined forces of Super Sonic and the Gaia Colossus.

Appearance
Basically, Perfect Dark Gaia resembles its immature form, but with extra features. Once matured, it grows four extra arms and its large mouth opens up, revealing hundreds of tongues which give way to seven aligned green eyes; three smaller ones on the sides and one large in the middle. It also gains two long tongues hanging out from each side of its central eye. Its seven tentacles (seen only in the 360/PS3 version) also move down its spine and their ends gain more shape, resembling snakeheads with smalls Mohawks and a green eye in their mouth.

Past
Perfect Dark Gaia has been the true form of Dark Gaia ever since its birth. Since the start of its conflict with Light Gaia, Dark Gaia would assume this form upon reaching full maturity in the earth's core and then rise from it to destroy the world, only to be defeated by Light Gaia and resealed in the core, losing its form in the process.

Sonic Unleashed
In Sonic Unleashed, Dark Gaia was interrupted early in its maturing process due to Dr. Eggman which broke it apart. When Sonic and Chip ended up in Dark Gaia's location after the beast had been reassembled, it absorbed its final fragment from Sonic's Werehog form, becoming physically complete. However, it was not until after the initial battle with Sonic and the Gaia Colossus that it fully regained its lost powers and became Perfect Dark Gaia.

Finally complete, Perfect Dark Gaia was ready to cast the earth into darkness and destroy the planet, but Sonic used the Chaos Emeralds to transform into Super Sonic and engaged Perfect Dark Gaia alongside the Gaia Colossus. At the end of the battle, Perfect Dark Gaia was defeated and fell into the earth's core, where it once again returned to sleep while its dark energy that had been covering the earth dissipated.

Powers and abilities
Perfect Dark Gaia wields the same basic powers as its premature form, but at the peak of its strength and capabilities due to having regained its full power. In this state, Perfect Dark Gaia stands as one of the most powerful beings in the series, being able to injure a Super State through brute force alone. Additionally, it could fight its supposedly equal, Light Gaia, to the point of overpowering him, all while taking on Super Sonic at the same time and wear him down to the point where he fainted from exhaustion.

In its true form, Perfect Dark Gaia's immense super strength and endurance have increased due to reaching full maturity. It is capable of completely immobilizing the Gaia Colossus in its grip and even overpower him in extended hand-to-hand combat. Likewise, it is capable of channeling extremely powerful energies into a more extensive variety of attacks than before; it can shoot large beams from its central eye without losing focus should the process be interrupt (unlike its premature form), project purple orbs, launch black balls with paralyzing effects, and channel its energies into its claws for enhanced slashes.

Through its tentacles, Perfect Dark Gaia can channel its energies to form and strengthen a force-field around itself that not even Super Sonic could penetrate periodically. Furthermore, Perfect Dark Gaia gains vast telekinetic powers that let it pick up enormous balls of magma without touching them and throw them as meteors. Like its premature form, Perfect Dark Gaia also has enough heat resistance to be submerged in magma without getting burned.

Weakness
Perfect Dark Gaia's weak points remains its various green eyes, like its earlier form, which are highly sensitive to damage. Though not to the same extend as its eyes, its arms are as well vulnerable enough to be temporarily paralyzed with a well-aimed Super Sonic Boost. It is also not immune to its own power, meaning it will take damage from its own energy attacks should they be knocked back.

Wii/PS2 Version
On the PlayStation 2/Wii version, the player controls Super Sonic as he flies in front of Perfect Dark Gaia. During the battle, the player can utilize the Turbo Boost to dash around on the screen and Deflect to throw the monster's projectiles back at him. Unlike most boss battles in the Sonic series, Super Sonic will lose ten Rings when hit by Perfect Dark Gaia's attacks. To defeat this boss, the player must collect Rings that float around to charge the Boost Gauge enough to use the Super Sonic Boost and hit each of Perfect Dark Gaia's eyes once. For every tenth Ring in the player's possession, the player can use the Super Sonic Boost once, but using it will also derive Super Sonic of ten Rings. At the same time, Super Sonic will use up one Ring per second, and losing all Rings will cost the player a life.

This battle is lengthy and tough. While collecting Rings, the player must move in the direction of Perfect Dark Gaia's still-open eyes, and when in front of one, a red target reticle will appear, indicating an opening. Such an opening also occurs when Perfect Dark Gaia roars. Upon launching the Super Sonic Boost at an eye, the player controls Super Sonic as he flies towards it. If the attack successful connects, the player wounds the eye and starts the process over again. With each eye though, meteors start appearing during the attack on the eye. Try to anticipate their trajectory and maneuver accordingly. If hit, Super Sonic will not lose Rings, but his attack gets canceled.

During the battle, Perfect Dark Gaia will attack mainly with its claws. As the beast cocks its arm back, a faint slash ﬂashes onscreen, illustrating where the attack will land. The faint slash is followed quickly by the actual attack, so move quickly to avoid it. As the player attacks more of Perfect Dark Gaia's eyes, it will slash faster and use all its six claws simultaneously. Quickly move to the screen's center to avoid the latter attack. Eventually, Perfect Dark Gaia will also start firing energy projectiles at Super Sonic. Follow the onscreen button press at just the right moment to deflect the shot back at the source. This will temporarily stun Dark Gaia, allowing the player to collect rings and target its remaining eyes. After hitting six eyes, Perfect Dark Gaia will reveal its central and much larger eye. After hitting this eye, Dark Gaia is finally defeated.

The time needed to S-Rank Perfect Dark Gaia is 7:30, total. Anything less gives a C-rank.

360/PS3 Version
On the Xbox 360/PlayStation 3 version, the battle with Perfect Dark Gaia is fought in multiple phases. Here, the player controls Super Sonic whose only usable move is the Super Sonic Boost, while playing as the Gaia Colossus during quick time events. Unlike other boss battles in the Sonic series, Super Sonic has a life gauge instead of a ring counter, which is increased when gathering Rings and depletes when Super Sonic is hit by floating rocks or Perfect Dark Gaia's attacks. If Super Sonic's life gauge is emptied, the player will lose a life.

In the beginning, Perfect Dark Gaia sets up an shield that Super Sonic cannot break. The players begin by charging towards Perfect Dark Gaia while dodging rocks and energy orbs. It is also important to gather up as many Rings as possible here to increase Sonic's life gauge, as there will be no other Rings available upon reaching Perfect Dark Gaia. After dodging the rocks, Super Sonic and Chip (as the Gaia Colossus) will reach the shield. Chip goes through the shield and distracts Perfect Dark Gaia, while Super Sonic must destroy the source of the shield, which appear in the form of serpent heads that extend outside it. These heads can be destroyed by boosting into them repeatedly, but the player must watch out for nearby rocks, which will make Super Sonic take damage. Chip has a life gauge as well, so the shield must be destroyed before Chip's life gauge is depleted or they lose a life. Sometimes, Chip goes down and Perfect Dark Gaia starts to attack Super Sonic through the force field. Here, it mainly attacks with a large laser or by throwing flaming rocks at Super Sonic. Chip will eventually rise though and distract Perfect Dark Gaia again for the player.

Once the shield is down, the player enters a cinematic gameplay section. Here, Perfect Dark Gaia grabs Chip with its six arms and starts charging its laser. Super Sonic goes in to save Chip by boosting into all six arms, which is done in gameplay by completing a button-pressing quick time event (,, , , , /, , , , , ). After that, Chip is freed and leaves Perfect Dark Gaia in agony, but it has still charged enough to shoot its laser at Chip. Chip takes heavy damage from the laser, but withstands (which is done in gameplay by pressing / sixty times within ten seconds). After negating it, Chip punches Perfect Dark Gaia. Super Sonic then comes in, and the player will have two options; either finishing Perfect Dark Gaia by boosting through its middle eye, or let Super Sonic gets it automatically. The boss ends immediately after that.

Videos
PS2/Wii = 360/PS3 =

Trivia

 * Perfect Dark Gaia is one of the two characters with the "perfect" prefix in their names, the other being Perfect Chaos. Both of these characters are final bosses.
 * In Sonic Colors, at the beginning of Asteroid Coaster Act 6, it looks like the roller coaster is coming out of a rock or planet that is shaped like Perfect Dark Gaia's head.
 * At the beginning of the 360/PS3 version, the fight against Perfect Dark Gaia is similar to Sonic & Knuckles '  Doomsday Zone (Avoiding asteroids and collecting rings). However in this game, crushing to asteroid takes a small part of Super Sonic's energy bar, while in Sonic & Knuckles, it only stuns him for a few seconds.
 * Perfect Dark Gaia bears a striking similarity to the God of Darkness from The Chronicles of Inotia: Children of Carnia. Both have a similar physical appearance, both draw strength from negativity and Chaos in humanity, and both seek to destroy the world.
 * The lava during the boss fight is noticeably brighter in-game, while in the cutscenes it seems to be darker and gives off less light.
 * In the Wii/PS2 version of the game, Perfect Dark Gaia's eyes are shown to have vibrant green eyelids, which close one at a time whenever one of the eyes is attacked. The eyelid on the central eye however, will not open until the other six are attacked. It is also worth noting that these eyelids are not visible in cutscenes.
 * Perfect Dark Gaia's in-game render shows him to have a slightly thinner head and larger eyes than his model in the CGI cutscenes.
 * If one looks closely during the shot where only Perfect Dark Gaia's head is visible above the lava, they will see that his central eye appears to be burnt off.
 * Looking closely right after Dark Gaia transforms, one will notice that only his central eye is staring at the Gaia Colossus while the others are all facing in different directions. This is also seen during the fight in the Wii/PS2 version of the game, in which the individual eyes can be seen shifting around and never looking directly at Sonic as he approaches them.