Shuumatsu Nani Shitemasu Ka? Isogashii Desu Ka?... (2027)

WorldEnd: What do you do at the end of the world? Are you busy? Will you save us? (SukaSuka) is a light novel series by Akira Kareno and Ue featuring a melancholic, high-fantasy story set 500 years after humanity's extinction. The story focuses on Willem Kmetsch, the last human, who acts as a caretaker for young Leprechaun girls who fight as "weapons" and are destined to destroy themselves. The 5-volume series, which focuses on themes of finding joy amidst tragedy, was adapted into a 12-episode anime and has a sequel series.

You can find the series on Wikipedia and a guide to the light novels on Orlandri Translation Company. Shuumatsu Nani Shitemasu ka? Isogashii desu ka?...