SAO Uchiha Izuna Time Travel

Uchiha Izuna's consciousness did not completely disappear after being killed by Senju Tobirama using the Flying Thunder God. His strong obsession to "protect Uchiha" and the special eye power of the Sharingan accidentally captured his soul data and traveled to the 2022 timeline of "Sword Art Online". The travel mechanism can be set to produce quantum resonance with the principle of "fluctlight" technology. When he woke up, he found himself in Tokyo, his body changed back into that of a five- or six-year-old child, and he had no identity record. While wandering the streets, he was discovered by the passing Kiritani couple (Kirito's adoptive parents) and adopted him. He became Kiritani Kazuto's adoptive brother, named "Kiritani Izuna".