Attack on Titan OVA (2013) - Episode 5 - A Choice with No Regrets: Part Two [English Subbed]

Summary :- After Levi, Furlan, and Isabel have joined the Scout Regiment, the former thugs plan to kill Erwin Smith and steal some documents during the scouting mission, as this was the job they were assigned to. However, during the 23rd Exterior Scouting Mission, Furlan and Isabel are killed by an Abnormal Titan. After Levi kills the Titan, Erwin reveals he knew all along of the true intentions of the trio, and encourages Levi not to regret his decisions. Levi decides to stay in the Scout Regiment and follow Erwin's orders from that day forward.