Yah, if I was a side character, if I knew about this, I’d be pissed. Thousands of casualties in the flooding world vs one girl (hello utilitarianism). Sorry, not sorry.
Also, there’s no context surrounding the sun-magic and perpetual rain, and there’s no solid reason (yet) behind choosing the girl for the sun-magic. I don’t know why what and who here, which makes it hard for me to enjoy the story.