Ore ga Heroine o Tasukesugite Sekai ga Little Mokushiroku!?
From MangaHelpers: Namidare Rekka has a very unusual birthright. After his 16th birthday, he will be drawn into many different stories. Each story has a heroine, and each story depends on him to be the hero. On his first day of high school, a strange uniformed girl that only he can see shows up. She claims to be from the future, and claims that his rescuing of many heroines is going to cause serious trouble for the future. It's not long after this encounter that his troubles begin. His childhood friend Satsuki invites him somewhere, possibly to confess her feelings for him. However, before she can, she's kidnapped! Rekka wants desperately to help her, but he finds himself being tossed into various sci-fi and fantasy worlds, each with their own heroines in trouble. Will he be able to get back to Satsuki? Will he be able to save all the others? How can he really tell the consequences of his well-meaning actions? [tethysdust]