Seven leaves have been laid.
A rabbit nibbling upon the dirt.
A pig wallowing in flames.
A rat wishing upon holier things.
A fowl with thunder in her throat.
A serpent by the water.
A bull full of hot air.
And a monkey sunk within himself.
The eighth, do I have, under mountain.
These seven keys are the seven leavesfrom which the mountain is the hilt.
-"Leaves", from the Legends
In the early days of Yuri's reign, the Trigram keys had not yet been unearthed. An old legend spoke of "leaves", and soon, one by one, determined adventurers discovered the mythic beasts which coveted these sacred keys. The only one not discovered was the Key to Mountain. Until Sagu's return.
In the years since he fled Koguryo after Mupa's banishment, Sagu bade his time, allowing his hatred to corrupt him into a vile warlock. He remained far from Koguryo, plotting his revenge when the time was right.
Rumours of a legendary weapon that might be formed upon gathering the keys spread throughout the kingdom, exciting many with the prospect of a great treasure. Sagu, knowing greed to be a weakness, set out to find the final key, searching the darkest caves and deepest woods. When he had finally discovered the location of the beast who guarded the key to Mountain, he risked and almost lost his life wresting the key from its claws.
His cold heart weakened, Sagu knew he must gather strength from the hearts of mythos to replace his own. When the stars became aligned, the powerful warlock used his powers to open the Vale, a land that had been hidden to mortal eyes for an eternity. To the East, lay Baekho, the great white tiger; to the North, was the black warrior turtle, Hyun Moo; to the West, was the mighty blue dragon, Chung Ryong; to the South, rose the fierce red bird, Ju Jak. In each of these directions, a heart lay hidden, though struck by the magic of Sagu's meddling, the hearts would appear on the mortal plane, vulnerable.
During this time, four clans were in existence - SunMoon Sect, Heavens, Bear and the Holy Dragon Order. Each clan had been called upon to protect a heart in the Vale from not only those with dark intentions, but from the other clans. It was known that Sagu needed at least two hearts, and used the coveted Mountain key as bait, to lure one of the clans into helping him. Thus, the War of the Hearts began.
The field was bloody as kin stumbled over the deceased, fiercely protecting their hearts, or moving in to steal that of another clan. Hour upon endless hour, day after day, the battle raged on, until finally, the SunMoon Sect claimed a second heart, and in exchange for the precious Key to Mountain, they delivered the two hearts to Sagu. Yet they bought more than they bargained for...