Attack on Titan - Before the Fall
Manga adaptation(by Shiki Satoshi) of the prequel light novel, of Shingeki no Kyojin(Attack on Titan)
The story follows the creator and the creation of the 3DMG, Ángel Aaltonen.
A mysterious youth named Kyklop and various other characters.
Set around 80 years before the main story of Eren & Co. In the year 770 to 790 of AoT's fictional alternative world.