The Holy Horn is a greater power created by the god 10,000 years ago that can be used for good or evil. When the god created the Holy Horn but when the forces of the Devils want the power of Holy Horn to end the world and bring back there defeated monsters, so the gods split the Horn in two pieces and scatted them across earth. The first piece was about to be published in Therical city museum and the second piece is at the bottom of the ocean. In episode 27 Terror horn and Oren brought two pices to gatherer to end the world. But episode 28 is the Rangers use to summon the Hermes Megazord card. So now the Rangers will use the Holy Horn in case of emergency.