Trailer

 is a preview chapter for Before the Fall manga, written by Ryō Suzukaze and illustrated by Satoshi Shiki.

Overview
Before The Fall - Prologue

Disclaimer: Attack on Titan Trailer is a short pilot story for the manga to be put in an issue of monthly Shonen Sirius October 2013 as a prologue
70 years before Eren's story begins, The first time a Titan breached Wall Maria, was erased from records. After 30 years of peace within Wall Maria, a Titan succesfully breached the Wall because the gate was open. This Titan ate a multitude of people including a pregnant Titan worshiper. The trailer end with Humanity having no way of killing Titans (the 3D Maneuver Gear has yet to be made)