Gaiamon is somewhat of a myth in the Digital World. Some say it exist, some say it doesn't. Some say Galacticmon digivolves into it by fusing with Earth, others say he was merely bluffing. Some say it really does exist thanks to the Grand One, and others just can't plain believe it really does exist. When Galacticmon mentioned that digivolving to Gaiamon was his ultimate plan, he never knew there was actually such a Digimon in the first place. Little did he know, the mere reference of the name Gaiamon would end up inspiring the Grand One to create Gaiamon in his own image, thus bringing Gaiamon into reality. Instead of having Galacticmon fuse with Earth, however, it now fuses with a set of gemstones called The Eight Spheres of the Planets, eight massively sized objects that are the source of Gaiamon's legendary power. And that's only the mere beginning, as Gaiamon's almighty size makes it 5 times larger than the moon that orbits Earth. Even though it is virtually unstoppable as it is, it always keeps it's old body parts it had as Galacticmon as an armored attachment in case it's power fails at all.
Digimon Bronze and Cobalt Versions
Gaiamon is the final boss in a massive boss rush containing all of the most powerful Digimon in the entire franchise, ranging from the 7 Great Demon Lords to the original 8 Digidestined Digimon's Mega stages. Gaiamon is faced immediately after Yggdrasil and has every stat at the new caps for in-game stats; 99,999 HP and MP, with 9,999 other stats at Level 999, making it the most powerful boss in the game in terms of stats. It's signature trait Overdrive makes it more powerful than a Super Ultimate. It doesn't favor any specific element in terms of resistance or weaknesses, so nothing is shown on it's status page for weakness or resist until you decide to train it's resist stats. It doesn't favor any element offensively either, and is a Balance type Digimon. Gaiamon can only be used in Multiplayer battles only under special conditions. Gaiamon's other signature trait makes it so only it can appear in the party. Although normally said to be planet size, Gaiamon will appear scaled down in-game.
The Gaiamon faced in The Grand Trial, however, is nothing compared to the Gaiamon faced in The Great Battle of Xros Wars, another quest in the game. Gaiamon is not in Armor Mode in The Grand Trial, but it IS in T.G.B.o.X.W.. Armor mode quarters all damage it receives, in addition to giving it Gaiamon's signature move: Plasma Gaia Cannon. Plasma Gaia Cannon hits all five zones, as every other attack move learned exclusively by Gaiamon's part of the Vemmon line does due to it's size. Gaiamon Armor Mode is NOT the most powerful boss in this quest, but it definitely seems like it would be due to it's signature trait Armor Mode grants it.