Born in 1989, 14 years old, a 7th grader at Odaiba Middle School. He is brilliant and the bearer of the Crest of Knowledge. He does not have a D-3, only his original Digivice. His partner is Tentomon. He is incredibly skilled with computers but struggles with English conversation, despite being good at reading and writing it (as coding would be impossible otherwise). He is not cold toward those he trusts, though he is intellectual and somewhat antisocial. He is polite to everyone but tends to keep his distance from others. He gets along well with the children he traveled to the Digital World with. He loves oolong tea and is the president of the Odaiba Middle School Computer Club. He is also a caring person. In the past, when they hitched a ride in the real world and the driver got angry about Koromon's mess, Sora lied and said she did it. The driver, thinking the pretty Sora (one year his senior) couldn't have done it, grabbed Joe (two years his senior) by the collar and shook him. Izzy jumped in shouting, "What are you doing?!" and fell under a bridge, which triggered Tentomon's Digivolution into his Ultimate form.

Joe Kido: 9th grade, born 1987. Sora Takenouchi, Tai Kamiya, Matt Ishida (French-Korean mixed, T.K.'s brother): 8th grade, born 1988. Mimi Tachikawa: 7th grade, born 1989, currently attending middle school in the USA. Yolei Inoue: 6th grade, born 1990. Kari Kamiya (Tai's sister), T.K. Takaishi (Matt's brother, French-Korean mixed), Davis Motomiya (likes Kari): 5th grade, born 1991. Cody Hida: 3rd grade, born 1993.

He has a witty sense of humor, is social, and has a kind personality. He occasionally offers advice to Izzy. An Insectoid Digimon at the Rookie level.

A warm person and Izzy's adoptive mother. Like her husband, she is a wonderful mother who understands Izzy better than anyone. Before adopting Izzy, she suffered the loss of her biological son to illness as an infant and worried that the adopted Izzy wouldn't open his heart to them or others. When Myotismon's henchmen invaded, she even shed tears while pleading with Izzy, who was glued to his computer, to run away. Though not his biological mother, she loves him more than anyone. After revealing the truth of his adoption and improving their relationship, she became a doting mother who showers her son with affection. She initially thought Tentomon was a doll and fainted when he spoke, but later grew close to him, calling him "Tentomon-friend."

A scientist and Izzy's adoptive father. A wonderful father who understands Izzy deeply. He was a distant relative of Izzy's biological parents, who were mathematicians. He adopted Izzy following the death of Izzy's biological parents in a car accident and the death of his own biological son. He kept the truth hidden out of fear of hurting Izzy but confessed after the Myotismon incident. Izzy already knew the truth but wanted to hear it from his father's mouth, which served as the catalyst for resolving the lingering emotional distance between them.