WHAT OUR FLARES MEAN
Titan spotted.
Abnormal Titan spotted.
An emergency occurred.
An order to retreat.
Change direction of the formation: Fired by the leader in one direction, and repeated by the relay soldiers.
This lets everyone know that the mission has been terminated, be it successfully or failed.
While leading the Female Titan through the Titan Forest, Levi Ackerman used a special shell that emitted a high-pitched noise.