Champions of the Deep (2012)

Max and May Champion live by the beach where they study a special martial arts known as The WaterStyle. One day, Max finds an ancient object by the shore. The kids learn this is the missing piece of The Sword of The Sea - a legendary and magical sword of the oceans - known as Aquavere! As they try to figure out the mystery of the sword, Max brings it to the beach, and activates the sword's power! When he does - the forces that battle beneath the seas know the sword has been found. The kids and their Master join forces with Kalyko - a Knight of Atlantis - to keep the Sword of The Sea in the hands of the helpers of the waters. And the Battles Begin!