Ken Ichijouji is a fictional character in the Digimon Adventure 02 anime series. Ken is the final member of the 02 DigiDestined, partnered with Wormmon and holder of the Crest of Kindness. Unlike the other 02 DigiDestined, he lives in Tamachi, which is next to Odaiba.
Formerly introduced as the devious Digimon Emperor (Digimon Kaiser in Japan), Ken works hard to try and atone for his wicked acts and eventually is helped along the way by Davis Motomiya as well as the others.
At first, upon learning that Ken is back and doing good, Davis wants to ask Ken to join the team, but none of the other DigiDestined approve the idea, particularly Cody. They are convinced that he is still evil when Ken orders Stingmon to destroy Thundermon in Primary Village. The DigiDestined believe that Thundermon is a real Digimon, but he is actually created from a Control Spire. Once the DigiDestined learn that in the next battle, they become more understanding.
Ken becomes a member of the team a little after ExVeemon and Stingmon DNA Digivolve to Paildramon, but despite joining them, Ken feels uncomfortable around the others, particularly Cody, who still strongly dislikes him for what he did in the past. However, Ken still takes part in clean up jobs and other tasks with the others, as well as helps out in all the battles against Arukenimon, Mummymon and BlackWarGreymon. Slowly over time, he begins to integrate with the the group and everyone, even Cody, becomes increasingly more accepting of his presence. Ken's place on the team is unconditionally cemented when he holds a Christmas party and invites everyone over to his home. There he is able to truly smile and laugh for the first time in a long while.
After Digimon begin to appear on Christmas Day, Ken and Wormmon go to Mexico City with Yamato "Matt" Ishida and Gabumon to help a Mexican DigiDestined, Rosa and her partner, Gotsumon, transport some loose Digimon back to the Digital World.
Later that night, when Ken gets home, he has a dream of his first time in the Digital World and the Dark Spore. The next day, Daemon and his Daemon Corps begin to appeared in Tokyo, and wreaks havoc while seeking Ken and the Dark Spore. But Arukenimon manages to convince Ken to come with her, using the children she "kidnapped" to motivate him.
Once inside the truck, Ken is confronted by Oikawa whom he had met at his brother's funeral a few years back, who reveals the nature of Dark Spore and copies its data into the other children, who had all been taken willingly. After the events which result with Daemon's banishment to the Dark Ocean and Oikawa's escape, Ken finally introduces his stunned parents to Wormmon and the following day, now aware of what was going on, Ken’s father is happy to help the children look for Oikawa.
By December 30, Ken and the other DigiDestined (with Matt, Koushiro "Izzy" Izumi and Joe Kido) are standing watch at Hikari-gaoka, waiting for the Dark Spore kids to arrive. When they are all congregated there, Oikawa arrives and begins the process that uses the Spores to convert the children's energies into an energy he could use to enter the Digital World. Ken demands to know why he was chosen and what the Control Spires are for. Oikawa, in demented glee, explains what his goals were and how Ken was involved, and proceeds to open the portal, unaware that the gate had been sealed off previously. The 02 DigiDestined follow him, only to discover that they aren't in the Digital World at all but some bizarre other dimension as a result of the sealed gate. This is when the ghost of Myotismon, an enemy of the former DigiDestined, reveals that he is behind everything. He explains how he entered Oikawa's body not long after his defeat and used Oikawa to help him in his revenge. He also abandons Oikawa's body and used the power of the Spores to digivolve into the newly resurrected MaloMyotismon, his enhanced Mega form.
The villain subjects the kids to illusions of their greatest desires. For Ken, on some subconscious level, his desire is to see himself punished by every Digimon he enslaved for what he did as the Digimon Emperor, as well as a chance to see his brother alive again. Ken's final epiphany occurs when the illusory "Sam" tells Ken that he can't change the past but can ensure a bright future for himself. Following his "brother's" final words and angry at having been manipulated yet again, Ken releass his guilt, crying out that he isn't the Emperor any more, that he is through with punishing himself and that he paid enough for his crimes. With that, he breaks through the illusion and helps fight in the final battle royale against MaloMyotismon.
Ken is notable among the main 02 Digidestined for being the only "new" member in that generation to own an original Digivice that later turned into a D-3, as well as the only one to have a crest of his own. Because of this, it is somewhat implied Ken was intended to be a DigiDestined more similar to the original eight.