Attack on Titan: No Regrets

Shingeki no Kyojin Gaiden: Kuinaki Sentaku (Attack on Titan Side Story: A Choice with No Regrets) is an ongoing spinoff manga illustrated by Hikaru Suruga and written by Gan Sunaaku with a story based on the A Choice With No Regrets visual novel. This manga focuses on Levi, and the The events happening in it are prequel to the main story by Hajime Isayama. There's currently one single prologue chapter published, with the first chapter coming in the next issue of Aria.