Destiny Star Girlfriend

Campus nobody Seiji is attacked by unhinged space demons — and saved by his classroom crush Yuuri, a magical girl. A surprise ambush leaves both of them fatally wounded. A mentor figure named Miss Fujiko binds their life forces with an enchanted thread. For the next three months of recovery, they must remain within one meter of each other at all times or the thread snaps. His dream girl, centimeters away, every waking moment.