The Final Battle was not going well for the Horde of Darkness. The battalions of orcs, so formidable at dawn, had been turned into just so much meat by midday. The serpentine naga suffered greatly in the afternoon sun, their body temperature raised and reactions slowed they were easily cut to shreds by onrushing Paladins. The Fire Giants had done a great deal of damage with their hurled exploding boulders until an enemy flight of pegasi had wiped out the sorcerers maintaining their magical defences, leaving them vulnerable to ice bolts shot by Good mages. The line of trolls was still holding, though it took an entire company of goblins running around to gather up the hacked off arms and legs for reattachment. As the Horde had dwindled the Necromancers had done their best, but it takes time for an undead to come into their own and a freshly raised minion of the Horde isn't even close to a match for a liveried Warrior of the Light in full battle regalia.
The Forces of Evil seemed to take it all in stride. They had, after all, lost in each of the previous twenty Final Battles, spaced every thirty years or so. Deep down his revenance the Infernal General knew that this battle would likely be no different. His main goal at this point being population control for the Orcs, he hadn't even bothered to array his forces in the most effective formation, instead maneuvering the Orc brigade directly into the path of the oncoming Cavalry of Virtue.
What neither the Infernal General nor his opposite the Anointed One realized was that this time, for this battle, the balance had changed. The mighty Orcus, long disinterested in this backwater parallel Prime, had finally grown weary of the constant stream of requests and appeals for demonic support from the Infernal General. Of course, Orcus had not sent his prized Balor to help in this great battle, for they were needed elsewhere. Likewise the Marilith, Nalfeshnee, Glabrezu, Hezrou, and Vrock had important duties elsewhere tending to various machinations as the Dread Lord Orcus explained in his message and was sure his minion on this plane would understand. The Infernal General did not, in fact, understand. That is, he did not understand until he saw the troops his Lord Orcus had seen fit to send: cambions. Half demons. Scorned by all true demons, objects of derision, sent to assist in this glorious conquest to come... The Lord Orcus was mocking him.
Mystical hadn't understood either, at least not at first. Her existence, some 20 years thus far, had been a dreadful one. Half-demons occupy the lowest rung of the hierarchy of the Abyss, harassed and tormented for fun and sport. She expected the wraith which had approached the cave she and two other cambions shared to be seeking amusement at their expense. Instead, it delivered a message. They were told to report to the Palace of Bone at once. There the three were met by a spectre, a minor functionary in the administration of Orcus, who ordered them to report to the Infernal General on a Prime Material plane and opened a gateway to send them.
Upon their arrival the General had continued looking over their shoulders at the closing gate, obviously expecting more reinforcements. Seeing none, he took the letter Mystical handed him, which contained a message she herself had not read. The General spent a long few minutes reading that message. When finished, his great shoulders slumped slightly, and he crushed it in one taloned hand. Spinning on a heel the General left them. He had not said a word.
That had been two days ago. Lacking any direction of where to report, the other two cambions had linked up with a unit of ogres where the minotaur captain agreed to accept them into his command. Mystical, finally realizing that Orcus had ordered them here to die merely to insult the Infernal General, vowed not to give in. Stealing away from the encamped Horde that night she snuck into the woods, travelling many miles until she reached the furthest perimeter of the Forces of Light.
Now wearing the uniform she had stolen that night, Mystical moved freely amongst the ranks of the righteous. Her magical healing abilities, long the object of scorn and derision in the Abyss, now reinforced her persona as a battlefield priest. She tended to wounds major and minor of the troops of Light, all the while making her way deeper and deeper into their rear area.
The Anointed One sat astride her horse at the crest of a hill, her sharp eyes scanning the battlefield below. The pegasi had done a fine job scattering the troublesome line of trolls on the left flank, and it would be at least an hour before the trolls managed to regenerate themselves back into a credible fighting force. By that time she expected the Horde to be in full retreat back to their warrens in the Underdark.
Mystical tended the injured in a large tent behind the crest of the hill. One eye always on the Anointed One, she bided her time and awaited her chance. That chance came sooner rather than later. A black robed sorcerer, either far braver or far more stupid than most, flew in fast and low from the front lines. Hands working furiously, the mage attempted to loose a fireball onto the hilltop as he passed. The mage was, of course, pincushioned with at least ten arrows before getting that close, but the arrow strikes had an unintended effect: the spell was partially cast. Lacking guidance the magical flames engulfed the sorcerer's body, and he screamed as he plummeted towards the hilltop. His screams completed the spell, which exploded point blank amongst the leaders of the forces of Light.
Mystical was the first to arrive at the scene. Being more resistant to heat than mere mortals she pushed through the scorching flames to the top of the hill. Blood and gore of slaughtered horses lay strewn across the ground. The Anointed One and her commanders were made of sterner stuff, though they had not escaped without injury. The Anointed One lay face down on the grass, bleeding from several wounds which were already beginning to close. Of extra-planar heritage herself, the Anointed One was certain to recover consciousness quickly. This gave Mystical only a few seconds to act. Removing a small silver vial from her pouch, she quickly unscrewed the stopper. She poured the contents of the vial into the open wound in the Anointed One's torso. The wound, which had been rapidly healing of its own accord, began to re-open. The substance was distilled essence of mandrake, a powerful poison to demons and, as Mystical had now confirmed, Devas as well. The potion had been given to Mystical by her mother, a succubus of some prestige in the harem of Orcus. She had told her favorite daughter to use it in time of direst need. Mystical cast spells of healing to close the gaping wound, sealing the poison inside the unconscious Deva.
The flames had subsided sufficiently for others to push through and come to the aid of their commander. Only a minor healer according to the insignia of her uniform, Mystical was pushed aside as more senior clerics crowded in. The injuries sustained by the Anointed One were serious and, strangely, her otherworldly body did not seem to be mending itself as quickly as it usually did. The healers began pouring energy into the angelic body, closing wounds and mending broken bones. They did not realize until too late that the real danger lay not in the physical wounds, but in the chemical coursing through her veins. The Anointed One died without regaining consciousness.
By the time the word began to spread through the ranks of the Righteous, Mystical was halfway back to the front. The devastating news swept the forces of Good like a torrent. The paladins could not hold back tears, dropping to their knees in agony. This suited the trolls just fine who, limbs newly reattached, began to wade through the throng like an avenging wind. The ogre magi, able at last to get spells past the defenses of the demoralized wizards, revelled in the destruction of the human and demihuman liveries. Mystical abandoned her disguise as she reached the battle front, rejoining the Horde of Darkness just as it broke through the enemy lines. The slaughter commenced.
The Great Feast had lasted for days. Unaccustomed to total victory, the Horde of Darkness had perhaps overdone it a bit. They hadn't left many of the snivelling surface dwellers alive to look forward to their lives of slavery, hadn't separated the gold from the platinum ornaments they looted from temples of good deities before melting it all down, and in some cases hadn't even pillaged the villages before burning them. In short, it had been one hell of a party.
Mystical did not know what to expect upon her return to the Abyss. She was, after all, not expected to return at all. One of the other two cambions would not, having fallen early in the battle when the company of ogres was beset by mountain dwarves. She expected to be punished severely, perhaps even killed, for her insolence in surviving.
She very nearly was. Niglisshibin, the spectre who had assigned them the task of reporting to the Infernal General's legions, roughly grabbed the other cambion as they stepped through the gate, draining away his life force in a few seconds. Eyes glowing, Niglisshibin looked directly at her. "Report to Grazzharden, the weapons master." is all he said, dropping the lifeless husk of the other half-demon as he did. Mystical did not know it at the time but she was spared her fate by Elik, who had taken notice of her actions on the Prime and marked her as one who bore further interest. Elik is a Balor, and a chief lieutenant to Orcus. With a few words in the proper ears he arranged for Mystical to receive training in weapons, magic, and assassination techniques. She did not learn the identity of her patron until much later.