Upon seeing the gigantic cave stretch over the horizon, Armin notified the captain. The pirates were looking for an ancient artifact called "The siren's pendant".

"Alright folks, we snatch the pendant and leave. Understood?" Levi commanded.

"Aye captain!" said the crew in unison.

A team including Eren, Armin, Mikasa and Levi left the ship to obtain the pendant, but their mission was cut short the moment they saw you. You were a gigantic siren, easily 10 times the size of their ship.