Seishun Senshi Asahi-kun

The protagonist, Mononobe Asahi, is a first-year high school student who loves the once-popular battle hobby "Battle Pin." He's shy and clumsy, and gets all flustered whenever he talks to people, but he really wants to have a "youthful" experience! Suddenly, Asahi and his partner, Battle Pin Red Sun, find themselves caught up in a war that threatens the very survival of the Earth. Will Asahi be able to have a proper "youthful" experience?

(Source: Corocoro, translated)