The undead was the force that had the greatest threat to the survivability of Shurima. Under the rule of Nocturne, the undead king, the Mortems were an Animus' worst nightmare. Just like Shurima, they had magic and spells that could destroy and create worlds. The Mortems even had an army that was twice as large as the Shuriman army. Although it seems like the undead could conquer Shurima at ease, there was one thing that hindered them from doing so. Long ago, the Mortems were banished into the infernal and fiery undead world of Gehenna because of a curse. They had been trapped their by Leonus' great grandfather, Leonidas when the undead rebelled and plotted the overthrown the Leo Dynasty. Their only hope of coming back into this world and wreck havoc upon those who banished them was hidden in the vaults of the great library. The Mortems could survive in Shurima because its climate was hot and dry just like their present world. However, they could not enter into the great the library because the curse prohibited them to do so. Only members of the Animus race could enter.
Although there were other worldly undead threats that Shurima faced, there were physical and present dangers that were from this world. The most atrocious and vile Anima who challenged Shurima's power was Hircum. Hircum was a goat-like creature who was once a high and respected official of Shurima. Unfortunately, power and evil blinded the great Hircum. He did not agree with Leonus' fair and just rule because he truly believed that Shurima possessed all powerful magic and spells to conquer the whole world. He believed it was their right and their destiny to do so. When he too tried to overthrow Leonus, the great lion king was enraged by his treacherous actions. He banished him from ever entering into Shurima. Hircum went around seeking for allies. But, no one dared to join him in his desperate battle for power. Then, Hircum committed the worst action that one can commit. He remembered that there was one group that would be willing to help him. They were evil but powerful, and they were unafraid of Shurima's power. They were the Mortems. Through his magical abilities, Hircum contacted the Nocturne himself. He pleaded for aid and power to the undead king. Nocturne agreed to help him but under certain conditions. Hircum had to swear his allegiance and soul to Nocturne. Also, Hircum must try and acquire the texts that could break Leonidas' curse. Nocturne promised him riches, power, and Shurima if he acquired the texts. Blinded by power and glory, Hircum agreed to every single condition.
With the Hircum, in the picture, the threat of Shurima became even graver. Unlike the undead, Hircum could enter into the library. Although it was improbable, it was not impossible to steal the text that kept the Mortems from entering this world. With the great task in front of him, Hircum plotted and planned for the demise of Shurima. He could finally be the ruler of the world.