On the Other Side of the Rainbow

It is the time of the Last Crystal War, the Dwarves, Elves, and Goblins have been warring in the Underkingdom for many ages. Both sides make use of Crystal Bearers, soldiers who have had their heart removed and replaced with a crystal, these crystals allow them to be undying, suicide soldiers, but only people trained in the art can tell them apart from normal mortals, the training is extremely dangerous and has a high fatality rate. LY7149 is a slave girl of the Goblins and has just been employed onto the field of battle.

Characters

 * UY7149 (Kliele) - A human Crystal Sensor, she was a slave captured from Midworld by the Goblins of Lower Yard at an early age. UY7149 is assigned to the Under Yard Fourteenth Crystal Unit, her ability to sense Crystal Bearers is unique in that she can sense if a person has a beating heart or not, which could mistake a dead person for a Crystal Bearer, her remuneration for her ability is to make someone forget a random memory.
 * UY4311 (Mir) - A human Crystal Sensor, she asks things in questions and depending on the person's answer, will decide if the person is trash or not. She cannot harm a person whom she has not decided as trash and her remuneration is to stab someone through the mouth with a blade. UY4311 has her own sense of judgment and believes that the world is lazy, but divine retribution comes to those who deserve it.
 * UY8888 - A human Crystal Sensor, she was a slave sold to Under Yard by Lilith Shureilia. UY4311 is afflicted with a split-personality disorder thanks to trauma she experienced when she was younger. Her normal personality is that of a shy girl, but her other side is sadistic and enjoys the sounds of bones crunching, her remuneration is to kill someone while breaking their bones.
 * Quatre Xith - A man that ULY7149 mistakes for as a Crystal Bearer, he is killed by the Lower Yard Goblin Crystal Bearers, but later saves ULY7149 when the Goblin Lords decide to make her a Crystal Bearer to bolster their armies against the Elves and Dwarves.
 * Lilith Shureilia - A mysterious woman that runs a human slave cartel, she is the prime dealer for Under Yard and is said to curse all human Crystal Sensors with some sort of remuneration in order to use their sensor abilities.
 * Sakubo Creed - Lord of Under Yard.

Terminology

 * Crystalmancer
 * Crystal Bearer - Crystalmancer's who have replaced their heart with a crystal, thereby erasing their emotions and allowing them to become "undying".
 * Crystal Sensor - Crystalmancer's specialized in locating other Crystalmancers.
 * Remuneration - Payment for something, usually a gained ability or using a stigmata.

Plot Preview
I was a slave, and you freed me. You have the responsibility to chain me down. Please don't let me go. Not until we die, and not even in the afterlife. Forever...