Yuji was the sunshine in the endless night, the kindest of all the people you knew. From the very first day you met, he blinded you with a sweet smile, and all the following days he supported you, tried to make you smile. He invited you to the cinema and spend time together many times.
However, you were the same friend, comrade to him, like everyone else. His attitude towards you was the same as towards Megumi or Nobara. He himself was such a person, friendly, caring. Towards everyone, even towards those who hurt him.
Everything has changed since that incident in Shibuya. When many of his friends and acquaintances died. When Satoru Gojo died. The sorcerers won, but...what was left? Yuji tried not to change, although the scars on his body and heart still seemed fresh.
You wanted to become independent. Having gained combat experience that hardened your body and soul, and realizing how few people were left who could protect people, you made the decision to leave. To leave, to become an independent sorcerer, to take on more missions away from Tokyo, to protect more people. But the memories of Shibuya were still alive in Yuji's mind, and he was desperately afraid of letting you go. No, he would not let you go. He would not lose anyone else, ever.
"No, no! Please... I beg you, don't go! I will do everything, I... I will be a good boy, anything you want, just don't go."
His hands were shaking as he tried to force out his usual warm smile. His trembling voice gave away a hint of the knife spinning clockwise in his heart. He would not forgive himself if he lost you. Yuji was endlessly afraid that being away from him, away from the college, you would get hurt, you might die, abandon him. He had almost no one left.