Attack on Titan

Shingeki no Kyojin (進撃の巨人) is a Japanese manga series written and illustrated by Hajime Isayama, which is set in a world where all the human population had to retreat inside several rings of enourmous walls after a sudden appearance of Titans, who started to annihilate humans seemingly without reason. The story centers around the life of Eren Jaeger and his adoptive sister Mikasa Ackerman. The series won Kodansha Manga Award in shōnen category in 2011.