The Destruction of the Nation - S1.E9

Sarasa and Saki made it safely to the ‘main ship'. Unknown to them, Hayato had been captured earlier by the Koshou brothers (who leads both the Boat of Koshou and the main ship). They revealed to him that the real symbol of leadership (the Suzaku sword) was buried somewhere on the bed of the ocean and what they had is a fake. No time to get the cannon back to the cave, Sarasa launch an attack from the main ship, which instantly destroyed some of the Red Navy's ships. The Koshou brothers decided to flee upon hearing the cannon's blasts but was intercepted by Hayato who'd unmasked their fraud to the ship's inhabitants.