Digimon

Digimon are creatures that used to be Pokemon, having undergone the second Transformation of Darkness. They get their name from the ancient Pokemopolitan language. Digis means "shadow" and mon means "creature." Digimon are creatures that are hostile to all other "lesser" creatures, meaning Pokemon and Dark Pokemon. The only recorded time that Digimon and Dark Pokemon have gotten along is when groups of both creatures came together under Marokainth in the Battle of Mount Elliot. Most Digimon today live peacefully in Digitar, though it is said that they are planning to use the recent power shift in the world to their advantage, and attack Pokemon once more.

The First Digimon
The first recorded Digimon was Marokainth. He became a Digimon after experimenting with his powers and the shard of the Stone of Geurre that is believed to be under Flaming Tower. It is said that in the year 617, once Marokainth was tranformed for a third time, into a Crazed Terror, he unleashed some power onto Pokemopolis, and a plague, known as the Stages of Darkness, overcame the Pokemon living in the kingdom. From there, they underwent the Transformations of Darkness and became Dark Pokemon. Soon after, many went on to become Digimon. A terrible war broke out - a three-way fight between Pokemon, Dark Pokemon, and Digimon. Within the year, Pokemopolis had fallen. For more information on the fall of Pokemopolis, please see the article here.

Scarcity
Digimon have been a rare sight throughout history. It seems that all Digimon migrate to the area known as Digitar as soon as they can. Throughout history they have done this, and have formed rudimentary societies. Not much is known about them because few Pokemon have even seen them.

DigiWars
Digimon have not been known to attack Pokemon often, because they usually have no reason and no legitimate organizational structure to do so. However, two instances in history have bucked that trend. Both assaults happened seemingly out of nowhere and both were launched against Pokemon Village. It is believed that these may have been the plans of Marokainth, though that is only conjecture at the moment. For more information on DigiWar I and DigiWar II, please see their respective articles.

Behaviors
Digimon are hostile creatures. They are usually unfriendly toward other creatures as well as each other, at least outside of Digitar. It seems that they find it easier to work together and create a society when they are at that location. It is not clear why, but more on that issue can be found here.

Types
There are many different kinds of Digimon, though scientists have never gotten close enough to study one. As they turn into Digidust when they die, Pokemon do not currently have much knowlege on the biology Digimon. However, Digimon seem to fall into similar elemental structures as Pokemon.