Jikuu Senki Mu (1991)

There used to be a continent called "Mu Continent", which was ruled by the king of the country called Prina. King Lars II suddenly turned the state religion of Neil into the evil religion of Max. Shortly after the Neil people were ousted from the sanctuary, the Queen of Purina suddenly disappeared. In addition, the newborn son of the king was taken away by someone. After the conversion, monsters began to appear in various parts of the continent. People began rumors that the people of Neil were manipulating monsters. It's been 16 years since then. The demons, who continued to grow in power, finally invaded Purina Castle. The seriously injured king runs to the remote village "Eribe".