Lord Devimon is the first major villain to face the DigiDestined, and is responsible for enslaving File Island with his Black Gears, hiding the Tags and Crests, and attacking the children directly and indirectly multiple times.
Devimon controls the Black Gears, which perform multiple tasks for him. He generally uses free ones that when summoned will fly towards and eventually collide with a Digimon, bending it to his will scrying mirrors to keep watch on the children. Another set of Black Gears are built into giant arrays as the core of File Island itself. When operated, they can cause the pieces of File Island to separate from or rejoin Infinity Mountain. Although Devimon has a strong control over the Black Gears, at one point it is stated that Devimon didn't create the Black Gears but mainly found them on File Island.and, sometimes, increasing its power and size, especially if the target is struck by multiple gears. There are also some that will serve as
Devimon is cruel and cunning, focused only on the spread of darkness. He waits for the perfect moment to strike, otherwise using proxies or manipulation to achieve his own ends. He has no qualms about using illusions to weaken his foes and striking during the night. Devimon also shows remarkable self-knowledge in that he acknowledges that he himself is a small fry in the grand scheme of things.
Before the DigiDestined ever arrive in the Digital World, Devimon takes control of File Island. At some point he finds a prophecy that says the DigiDestined will destroy him, and so he hides their Tags and Crests across the Server Continent. Although it is never specifically mentioned, it is possible that Devimon received the tags and crests from Piedmon, who had originally stolen them from Gennai before the start of the series.
When the DigiDestined arrive on File Island, he indirectly attacks them with Black Gear infected Digimon and puts the renowned Leomon and Ogremon under his thrall. The children eventually climb Infinity Mountain and reach his mansion. There, he gives the DigiDestined an amazing dinner and a nice, hot bath in a sauna—all of which are designed to lull them into a false sense of security so that he can strike while their guards are down. He splits the island using his Black Gears and separates the DigiDestined, but his attempts to kill Taichi "Tai" Kamiya are stopped when his Digivice frees Leomon from his spell.
Fortunately, the DigiDestined manage to find ways to return the pieces of the island to their original state. As he observes Takeru "T.K." Takaishi's resolve to fight, Devimon knows that he has to kill him and his partner Patamonbefore they can digivolve to the Champion level. To this end, he sends Leomon and Ogremon to kill the pair, who are only saved by T.K.'s brother Yamato "Matt" Ishida, Tai, and their Digimon Garurumon andGreymon. When Leomon seems to be losing, he sends more Black Gears to power Leomon with darkness. Using the light of their Digivices, however, Tai and Matt banish both the Black Gears and Devimon's own influence, as the Digimon force Ogremon into retreat.
Unfortunately, all of this is to according to his plan. Leomon leads them directly to him, where he has absorbed a large amount of Black Gears, as well as Ogremon, to increase his size and strength. Now standing nearly as tall as a mountain, he shrugs off the Champion Digimon's attacks and tears through the ranks, effortlessly flinging them away. With the rest of the Digimon incapacitated, Devimon turns his attention toward T.K., whom the prophecy says will defeat him. Attempting to crush him in his hand, Patamon instead interrupts and digivolves into Angemon. Angemon deletes him with a "Hand of Fate" empowered by the light of the Digivices and Angemon's life. Though Devimon is defeated, he reveals that there are many other evil Digimon just as powerful as he is along others that are even more powerful, and he gloats that even Angemon will not be able to handle them, as he cannot even defeat Devimon without sacrificing himself.
Millenniummon revives Devimon during his birth, and he makes his home on File Island in Devimon's Cave where he holds Koushiro "Izzy" Izumi and Mimi Tachikawa, as well as their partners, hostage. Ryo Akiyama breaks into his cave and defeats him and his Devidramon guards, freeing the DigiDestined. Afterward, Izzy and Mimi send their partners, Tentomon and Palmon, to aid Ryo in his quest.
In Digimon Adventure 02, Devimon briefly reappears while the Digimon Emperor is searching for the piece needed to bring Kimeramon to life. When the Emperor finds the Dark Whirlpool and goes down into it to find the piece, he finds the broken remains of Devimon. The Emperor disregards Devimon's taunt-like warning that "the powers of darkness cannot be controlled" and harvests his data for what become the arms and DigiCore of Kimeramon. However, Devimon's influence causes Kimeramon to rebel against the Emperor, and his voice returns to taunt him again until Kimeramon is destroyed by Magnamon, and Devimon's data with him.
- The Touch of Evil (Death Claw): Stabs his claws into his targets and infuses them with dark energy to put them under his thrall.
- Death Hand: Unleashes a blast of unholy energy from his hands.
During Ryo Akiyama's efforts against ZeedMillenniummon, he has a chance to go to the past and save Takeru "T.K." Takaishi and Patamon from Devimon and two Devidramon while he is being attacked on File Island. If he does so, he recruits Patamon to his cause.
Devimon is the boss of the "Yami no Shisha Devimon" chapter of Digimon Tamers: Digimon Medley. Leomon and Ogremon his minions, and he taunts Tai and Matt before retreating to Infinity Mountain's summit, where he is defeated.
- ↑ Devimon: "You have used up all your power; that wasn't very smart of you Angemon, now you are no use to anyone! You can't escape from the Dark Forces, evil is everywhere, so don't savor your victory. There are other Digimon just as powerful as I am, some of them are even stronger—I wonder what you'll do when you run into them? You haven't won at all, what a waste of time!"