Digimon Adventure:

Etemon was the first major foe other than Nanomon the Chosen Children had to battle with after their arrival at the Server Continent. With the help of his Dark Network, it was able to monitor everything which happens in its territory.

Digimon Xros Wars:

Some Etemon serve Musyamon in the Shinobi Zone. They pretend to be Shoutmon's fans in order to find the Code Crown.