Byproducts of the chaos Apocalymon had on the Digital World, the Dark Masters were started by Piedmon, with MetalSeadramon, Machinedramon, and Puppetmon joining him when that began their reign of terror throughout the Digital World while the DigiDestined were fighting Myotismon. Prior to the events involving the DigiDestined, the Dark Masters defeated the four Sovereigns and sealed them away. When the DigiDestined returned to the Digital World, they discovered that the Digital World was warped (due to Apocalymon) and the Dark Masters used some of the land's data to form Spiral Mountain with their base of operations, Piedmon's castle, on top. The Dark Masters outmatch all eight DigiDestined, Chuumon is killed by Piedmon, and Piximon sacrificed his life to get the DigiDestined away from the Dark Masters. The DigiDestined climbed Spiral Mountain, and defeated each of the Dark Masters with some help from their old Digimon friends. The Dark Masters were defeated and the kids had to fight Apocalymon.
Digimon 02
The Dark Masters were mentioned by Digitamamon during Yolei Inoue's problem getting him to accept their money.
Piedmon - From the Dark Masters' base of operations, he rules the wasteland with LadyDevimon (who serves as his bodyguard) and a large group of Vilemon.
Victims of the Dark Masters
Chuumon: When Piedmon threw a dagger at Mimi, because her whining got on his nerves, Chuumon jumped in front, dying a few seconds later in Mimi's hands.
Piximon: He saved the DigiDestined after their first defeat by the Dark Masters. In order to hold the Dark Masters off, Piximon decided to fight them. Although his fate is never revealed, it is most likely than he did not survive this encounter.
Cherrymon: The closest thing Puppetmon had to a friend, Cherrymon was destroyed by the Dark Master when he warned him not to underestimate the DigiDestined.
WaruMonzaemon: When Machinedramon heard from WaruMonzaemon that the DigiDestined were still alive, he "rewarded" the bear for not alerting him sooner, thus killing him (In the English anime he just shot off his arm).
