Katsuki and Sagara both have things that they regret, and things that have hurt them in their lives, they both are kind, caring, and respectful of others, both live semi isolated lives, with few friends, Sagara is good at massage with his hands, Katsuki is good at running, he can help her with his massage techniques, and she can help him to maintain a stable emotional balance. Already Katsuki can't live without Sagara in her life, and if Sagara would admit it to himself he feels the same about Katsuki.
Katsuki and Sagara both have things that they regret, and things that have hurt them in their lives, they both are kind, caring, and respectful of others, both live semi isolated lives, with few friends, Sagara is good at massage with his hands, Katsuki is good at running, he can help her with his massage techniques, and she can help him to maintain a stable emotional balance. Already Katsuki can't live without Sagara in her life, and if Sagara would admit it to himself he feels the same about Katsuki.