Ken Ichijōji's journey unfolds across multiple series and films. His childhood was marked by trauma stemming from feeling overshadowed by his older brother Sam, a child prodigy. This neglect fostered jealousy, culminating in Ken wishing Sam would disappear shortly before Sam's accidental death. Ken bore intense guilt over his perceived responsibility for his brother's passing. A Digivice intended for Ken emerged from Sam's computer, transporting him to the Digital World where he partnered with Wormmon and aided Ryo Akiyama against Millenniummon. During this battle, Ken shielded Ryo and became infected by a Dark Spore. This event warped time, returning Ken home the same day he left. Sam discovered Ken with the Digivice, berated him, and kicked him out of their room, intensifying Ken's anguish. Later manipulated by Yukio Oikawa via email, Ken used the Digivice to enter the Dark Ocean, submerging it to create a corrupted D-3. This activated the Dark Spore, eroding his empathy. Believing the Digital World was a malleable game, he became the tyrannical Digimon Emperor (Kaiser), enslaving Digimon with Dark Rings and Spirals. He excelled academically and athletically in the real world but viewed others with contempt, considering them "insects." His reign involved constructing Control Spires, creating the synthetic Kimeramon, and battling the new DigiDestined. After Magnamon destroyed Kimeramon, an event triggered by Wormmon's sacrifice, Ken realized Digimon were living beings, not data. Overwhelmed by guilt for his atrocities, he collapsed emotionally. Returning home, he suffered amnesia before wandering back to the Digital World. Confronted by abused Digimon, he tearfully apologized. Reunited with Wormmon reborn as Leafmon, he vowed atonement. Destroying his Control Spires initially met distrust from the DigiDestined, especially Cody. During a crisis at his fallen base, Davis Motomiya's insistence on teamwork resonated, enabling DNA Digivolution between Stingmon (Wormmon's Champion form) and ExVeemon into Paildramon. This solidified Ken's place on the team, though lingering guilt and Cody's resentment caused discomfort. He later learned Arukenimon reactivated his Spires using dark magic. In *Digimon Adventure 02: The Beginning* (set in 2012), Ken is a university student studying for the police entrance exams. He maintains a close, peaceful bond with Wormmon, often reading together on campus. When a giant Digi-Egg appears over Tokyo, Ken joins the other DigiDestined in investigating Lui Ohwada, who claims to be the first DigiDestined. Ken participates in the battle against Ukkomon, which challenges the nature of Digimon partnerships; his direct role in resolving Lui's trauma is supportive rather than central. By adulthood, Ken marries Miyako Inoue (Yolei), becomes a police officer, and has three children: a daughter partnered with Poromon and two sons partnered with Minomon and Leafmon. This future reflects his full redemption and stable life.