Heartwarming / Sumire 16-sai!!

• Everyone thanking Sumire one last time for changing their lives. Creepy old man or not, it's pretty heartwarming.
• Believe it or not, the old man counts as one. He may pretend to be a high school girl, but he changes people's lives. He gets Renge to not be afraid to try and make friends despite her being bullied all of middle school, he convinces Akebi's father to allow her to live a normal school life that she wants to live and he convinces Mizuki that the world isn't as boring as it seems and that there's interesting kinds of people that she'd never meet if she continued to be her cold self. And then the last chapter reveals that they're not the first girls that he's helped. He's essentially like a volunteer guidance counselor, doing all of it for nothing but helping young girls enjoy their high school years.
• Renge and Akebi's faith in the old man / Sumire's capability to give his/her all during the boxing match:
  Akebi: When it comes down to it, he's stronger than any yakuza.
  Renge: Or any bully. Captain, you just have to believe in him.