Hundred

When an alien life form called "Savage" begins attacking humanity, the only weapon capable of fighting back is a technology known as "Hundred." Hayato Kisaragi, a teenager who survived a Savage attack, has the highest compatibility with this weapon and is recruited to train at Little Garden, an elite military academy on a battleship. As he undergoes rigorous preparation for the coming battles, Hayato quickly catches the attention of several female classmates and finds himself tangled in various conflicts while fighting the creatures that have overrun Earth and endanger its survival.