Dark Gaia is spawned by Doctor Doom and quickly overwhelm Earth with i'ts trillions minions. S.H.I.E.L.D and the military is possessed by Gaia minions in a very short amount of time. The Living Tribunal senses an extremely powerful force of Omiversal scale (yes, Dark Gaia is Omniversal) and summons Franklin Richards to aid the Earth heroes. But he arrives to late. Dark Gaia turns into Perfect Dark Gaia, his most powerful form enough to consume The Universe with Darkness.
Perfect Dark Gaia
|The abomination grows strong on the negative energies of the world, sleeping within its core for millennia in wait...|
Perfect Dark Gaia is one of the most powerful beings in Sonic universes. Along with The Time Eater, Solaris and Mammoth Mogul. During the climatic battle against it, Dark Gaia was able to fight Super Sonic to the point where he ended up fainting from exhaustion, something no foe so far has been capable of, and at the same time, take on Light Gaia, a being who supposedly should be on the same level of strength as Dark Gaia itself. Additionally, Dark Gaia (as shown in its perfect form) is one of the few enemies that is able to hurt Sonic while he is in his super form. Perfect Dark Gaia also tanked Light Gaia with Gaia Colossus using the powers of the seven chaos emeralds!
Gaia has his trillions of minions and the majority of Earth at his disposal to aid in his fight. In addition, Dark Gaia also posses all the villans. All those who weren't posses works along side with him for pure fear.
Earth team counts with Frankin Richards, The Avengers, X-men, Fantastic Four and the rest of The Super heroes. They have little time to react, otherwise too many super heroes can become possessed.