"I saved Tonbokiri?" It sounds impossible, but it checks out. The change started as soon as he started laughing. He saved him. Yes, Tonbokiri is bringing up other theories, but Keigo wants to focus on that part.

"You're right. My color is blue. It took crying to turn me back, which is kind of blue. So laughing could be yellow because it's happy!"

Keigo has the decency to look sheepish about his recent branch murder when Berkut mentions "treatment of their habitat." He was just trying to help and a single leaf wasn't going to be enough!