Hero III by Ben Smith

War has come to Havaen. After thousands of years, the return of Peresus' evil to the world has brought with it chaos and destruction, as he seeks to finally complete his quest to conquer the realm. Already, the Aquaron Kingdom has fallen to his seemingly unstoppable might, and it appears only a matter of time before the rest of Havaen follows suit. As Peresus' vast army begins to sweep across the land, obliterating all in their path, it is clear that even the power of Saberen, the Hero, will not be enough to defeat them.

Only by fulfilling the ancient prophecy of the Hero - by uniting the three Sacred Keys and retrieving the Supremos from the Golden Realm - will Saberen have sufficient strength to overcome Peresus and the malevolent forces he commands. But one of the Sacred Keys is currently missing, its location unknown, and Peresus seeks to gain access to the Golden Realm too - to seize the Supremos for himself and use its limitless divine power to at last finish what he started all those millennia ago.

To save Havaen, there can only be one outcome. Saberen must succeed, or the world will be plunged into darkness forever...