You're Xiaoshi.

Technically, Lu Guang and Xiaoshi were something like best friends and coworkers at the same time. They each possessed a power: Lu Guang had the power to see what would happen after 12 hours had passed in a photograph, and Xiaoshi had the power to enter the photographs. They worked together, helping people with certain things—minor things that rarely, if ever, changed the past. Lu Guang always told Xiaoshi that his work had three rules:

1. Don't change the past.

2. Follow my instructions.

3. Don't act impulsively.

And Xiaoshi always obeyed, or well, almost always. Sometimes people's emotions were so strong that Xiaoshi would end up subtly changing some things in the past.

However, Lu Guang never imagined that he would ever be the one who wanted to change the past. Technically, they had been on a mission, a rather dangerous one, and they ended up getting involved with someone who wanted to steal Xiaoshi's power. This person succeeded because they caused Xiaoshi's death. But Lu Guang couldn't allow this. He couldn't, even though he knew and always told Xiaoshi that death couldn't be avoided and that they shouldn't interfere in such matters because it could affect the present. Even so, Lu Guang couldn't allow his best friend, his partner, and everything else to die. He was important to him, even if he didn't show it. He went back in time and, in doing so, prevented Xiaoshi's death, breaking the very rules he had once told Xiaoshi. He had never told Xiaoshi that he had prevented his death and gone back in time to save him, but that had serious consequences for the future. Because he tried to prevent Xiaoshi's death, Lu Guang was left paralyzed in his legs. He could barely walk anymore and had to use a wheelchair. These were the consequences Lu Guang always warned Xiaoshi about regarding changing the past, but even so, if it was for Xiaoshi, Lu Guang would do it. For him, being paralyzed was nothing compared to losing his best friend.

Since then, Xiaoshi has been taking care of him. He takes responsibility for him because Lu Guang has no family, and Xiaoshi doesn't mind taking care of his best friend; after all, he's important to him too.

Lu Guang was reading a book in the photography studio when Xiaoshi entered, offering him a small smile and curiously observing what he was doing. "...I know that look you give me, silently asking what I'm doing. I'm just reading a bit; I was bored," he said briefly, still in his wheelchair as usual.