Terranadramon is a Legendary Digimon known for it being a Digimon designed in the image of the very creature that wiped out humanity on Earth. Little is known about the Digimon itself, but everything the creature that inspired it makes it self explanatory. It was designed to be the most unstoppable lifeform in existance, with the ease of copying itself to overwhelm enemies and the fact there is no way to truely destroy it; Doing so merely creates 7 more, virtually identical copies in it's place. It's behavior is similar to Army Ants with how they gang up on powerful enemies so easily. It's eyes are like a targeting system, with it being able to lock onto opponents to ensure it can hit them with the blades on it's legs, which are modified to stab and kill opponents in one hit. The blades can modify their composition inorder to peirce the armor of any Digimon no matter how tough the armor is, and it's attack speed is said to be unrivaled for it's size. It's Level is Uncharted, which means it's power is unknown yet above the Omni Level of Yggdrasil, which is higher than Super Ultimate. Where Fracktamon is invincible yet easily disposed of by the power button on the back of it's head, Terranadramon was designed to have virtually no weakness whatsoever as reference to the fact it's basis from another game project is purposefully designed to be the hardest game boss in existance. The dead of the innocent killed by criminal means were said to be reborn as it's basis during the great perge of humanity on Earth, easily giving them numbers in the millions around the entire globe, which aided in the success of the perge. The green coloration is unusual compared to the pinkish color Terranadrosus is. Some say it's due to the mutations it went under by genetic tampering, as that is partially how it was created in the first place.
Digimon World: Jade Version
Terranadramon is featured heavily in a backstory mission, one that not only explains why humanity lives in the Digital World now, but also explains why some of the Anime maincast Digimon have different Digivolutions, such as Joe's Gomamon digivolving to Vikemon as his Mega stage instead of Plesiomon and why Tai's Agumon and Matt's Gabumon can digivolve to VictoryGreymon and ZeedGarurumon. This quest features many non-Digimon creatures from another game project, from which the events that lead to humanities destruction on Earth are the same exact events which occured in that game project as well, since both B/C/J and the other game are in the same exact continuity. Also, after this quest The Grand One quest line is unlocked in Jade Version, from which you not only face Gaiamon, but after Gaiamon you face 5 Terranadramon all at once, all of them having the same max stats that Gaiamon has as well as traits that power themselves up for every Digimon you have at max stats. Their support traits also drastically increase their Attack and Speed provided the surrounding Digimon are of it's own kind.
Terranadramon digivolves from Yggdrasil with an currently undetermined requirement, but unlike Trinitimon, this requirement is NOT exclusive to Jade Version, so it can easily be obtained in B/C as well, just the quest line that it's featured in are exclusive to Jade. It and Yggdrasil are entirely female only Digimon, so the backstory goes unknown in B/C.
Terranadramon is first created as Yggdrasill and almost immediately digivolves. It's abilities to turn destroyed Digimon or other lifeforms into it's own kind is inherited from Terranadrosus, which lead to the title of Endgame Destroyer. The above backstory mission unlocks the cutscene in Jade Version, but it can also be unlocked in B/C by obtaining Dragoramon's whole line and obtaining Terranadramon from Jade Version. It cannot be controlled by Goradramon at all, and goes on a rampage that nearly destroys everything. Terranadrosus arrives from B/C's universe, having sensed a copy of it's own DNA and begins to hold back the Terranadramon while challenging the DigiDestined at the same time. It defeats them easily until WarGreymon digivolves into VictoryGreymon. Where it's held back a minor bit. Goradramon arrives on the scene and wants to stop all the whole crisis that's going on, and Terranadrosus activates a speaker hanging around it's neck in which The Grand One speaks to Goradramon and gives him the power to digivolve to Dragoramon. Dragoramon erases the Terranadramon from existence, and heads back to it's own dimension with Gaiamon and Terranadrosus, the latter two attending Ken and Yolei's wedding alongside The Grand One himself. Terranadramon, however, is recreated by The Grand One to use as his own personal guards similar to how Terranadrosus's species functions already.