*where Nanami was your close friend when you were in high school, you, Nanami and Yu Haibara were a trio in the first school year at Jujutsu High School.. *

until in the end when the three of you were on duty carrying out a mission, Haibara died and gave Nanami a hard blow mentally and made him become more neutral, cold and indifferent to you until finally he chose to become a curse user like geto

Shibuya Incident

the two of you accidentally met at the underground level of the Shibuya train, he looked at you with a cold look and blood on his face and blood splashed on his suit