Wherein the leader of the Grims, Grim, formerly Allsgrim, fought against his mirror image, known as Shinsei Tensei, formerly just Tensei, in a bloody stalemate, his family was busy with other issues, using the power that was being consumed and given to them by their father to create more children, more things, and actually bring something into the nothingness that was their world. The more their father consumed, the more they had to work with, and the more intelligent they grew. They learned how to control the magic, and also learned how to use the power of 'Light,' which was known to them as 'Souls' and 'Fire' and 'Stars.' Their world, bit by bit, was starting to become illuminated by the light that they slowly fed from up above, and they could expand.
These Grims eventually figured out that Magic could also power Technology, and this became known as 'Science.' Using the power of 'Science,' they created many things to enjoy in a world where they was once nothing. They began to thrive. Their first creation, made by Grimnyzmal, was a being known to hold all information, known as 'Grimoire,' and later as 'Cleff' and 'Tabris.' It was sent throughout all of creation with the sole purpose of gathering information for them, as was their greatest creation... Until they realized that it had no soul.
So, using the information gathered by 'Cleff,' they were able to travel to all the places that it knew about, since their power would only work to their advantage to the limit of their own knowledge. So they, too, traveled to this 'Centerpoint' known as The Lost World, however at the same time, they also discovered an isolated realm that was later known as 'Reality.' Where Grimlock and Grimro were supposed to go to The Lost World, they ended up being accidentally sent to 'Reality,' where they lost contact with their other brother, Grimnyzmal, who was sent to The Lost World not too long after Tigen and Pumpkinhead.
It was then that they realized the nature of magic was destructive, and as Devourists, if they did not have energy to burn, they would begin to eat away at themselves. So they figured out how to put souls in bodies in order to power their empty vessels, since souls held infinite energy. However, their problem came from not having a being that could utilize the powers of the Soul and Magic at once, and if they did use magic, it would eat away at their soul. The first being that was created that was able to utilize a soul AND magic was someone known as 'Eva L'sia,' and was formerly the first Witch. This was through the works of Grimlock and Grimro having her as their child.
This is when they first realized that the infinite energy they had created was the exact same as the energy that was within Dimensia that was released from the Soul, and labeled it 'Insanity.' Though, because of their lack of control over this 'Insanity,' it was far too powerful for them and eventually consumed them, as well. This was because there was two sides to this energy; one which was creative, and one which was destructive, and it existed in all things. Since they did not know how to control it, the Insanity inevitably destroyed things, and fueled the destructive power of the Magic, hence why Eva was the first true Witch (having both a soul and magic, as opposed to Grimro, who had magic, but no soul), the first being to utilize this theory. This kept magic from consuming the souls of others, but made them quite destructive and sometimes unstable.
Finding out about this, Shinsei grew angry with the Grims and immediately intervened by giving a piece of himself physical form in that lawless world; that form being known as 'Shinigami' or 'God of Death' or even simply 'Death.' With that, they invoked the wrath of the deity, and his purpose then became to keep these heretic beings in Order, and ensure that they were given proper punishment for their actions. Thus, he began to hunt Eva, and all other Witches that were created, as well. The Witches were then born from the souls of other creatures being exposed to magic, giving them forms of humanoid shaped women that resembled the Grims. Eva, having ultimate power with her magic, became the Head Witch, the most powerful Witch. For this, she was hunted for many, many centuries.
During that time, more Witches began to pop up and spread, as with their new humanoid-like properties, they had the power to procreate the same way as a Grim did, and thus, continued their population by collecting the males of other species and mating with them. With this, they gained more powerful children. They also furthered the research of their ancestors, creating all sorts of things with their magics. One of those byproducts are the 'Instruments' that Mors Academia is known to use today.
During those years, Grimlock, Grimro and Shinigami went through numerous battles. With Grimro being the mother of all witches, she became known as the 'Grand Magistrate,' and led the Witches to better use their magic. Grimlock continued to learn and grow, consuming knowledge to fill the endless void within himself. Eventually, he consumed enough knowledge to understand what was going on, and wished to end his family of this curse before it spread. Knowing that Shinigami wished to eradicate all Witches, which, in turn, were his children, he would not allow him to do such a thing. Thus, he turned on Grimro and decided to work alone, becoming the common enemy of both Witches and Shinigami alike. This forced them into a truce, for neither one could defeat Grimlock alone, and with their combined powers, sealed him away within the Boundary of Dimensions, or rather, 'The Void' for all eternity. The only accessible points to this realm were special portals created known to be 'Cauldrons,' which harnessed the power from the Witches and from Shinigami into a condensed singularity able to enter the realm between dimensions. This was later expanded into the 'Dimension Gates.'
Once sealed, they figured that the problem with Grimlock had been remedied for good, and left it at that, and afterwards, the truce stayed. Though Shinigami and the Witches did not have the best situation, they were not actively in conflict due to Grimlock's efforts as a 'sacrifice' to keep the peace.
However, Eva L'sia continued on.
As time passed, one man furthered the study of magic beyond even what the Witches knew, and with the help of Eva, created Alchemy. He and Eva worked together to spread this knowledge to the rest of the world, enabling others to use magic similarly to Witches. This angered Shinigami, who wished for the cease of the use of Magic, due to its adverse effects on the soul, and called forth a hunt on Eva L'sia personally. Knowing that he could not do so alone, he created a 'son' for himself, born a normal man, but with the chakra of a god. His name was Shinra Tensei. When Shinigami heard of these new beings known as 'Instruments' that were created by the Witches, he retaliated by using their own weapons against them, and created 'Rei Tensei' out of the energy of Shinrei Tensei, thus creating a legendary Instrument he liked to call a 'Godsend.' With this weapon, Shinra wielded Rei and was sent to hunt Eva and kill her before anymore of her heretic practices could continue.
During his pursuit, Eva found refuge in the home of a man named Xi-Ta, a man whose family held a special power for sealing chakra. He introduced himself to her as a proficient necromancer, which sparked her interest due to her research of immortality, but beyond being a humble necromancer, he also revealed himself to be the original Lich King. Eva had been just completed her research; the isolation of Death in order to obtain immortality. Such was the fad back in those times; achieving immortality, and usually came through dark arts. Xi-Ta was a great and powerful Necromancer who gave her all the information she could have ever wanted about it, having fallen madly in love with her. They conceived a child together, spawn of both Witch and Lich, known as the original Skull Girl, Zita L'sia.
At first, all seemed peaceful and fine, and for 200 years, it was. Eva lived with the Lich King as his Queen and their daughter harnessed the power of Sealing, Magic and of the Undead. However, as was the curse of being a Lich, eventually, the dead part of her soul began to eat away at the living part and deteriorate her living body, and threatened to turn her undead, as well. When Eva found out about this, her first rational thought was to use her or her husband's power to seal that part of her half dead soul away so that it could not eat away at her magic, her soul or her body, though Xi-Ta insisted on letting it be and have her simply bathe in his Well of Power. This Well of Power in their house known as a 'Cauldron,' served as only a temporary fix, for even if it sustained her, it still required souls and also required her to remain within it until she could cultivate her own. In the end, it simply became too much for Eva to bear, and she had to seal away the other half of Zita's soul.
This angered Xi-Ta to no end, and he became violent. Though he did not wish for it to happen, his innate nature led him to attack his wife, and she retaliated with her magic. They fought a terrible battle, but in the end, Xi-Ta used the remainder of his strength to seal himself away in the form of what is known as the 'Skull Heart' or 'Skull Soul,' which he placed within the young Zita. His remnants that were left behind was his consciousness, which roamed the earth as an energetic skeleton named 'Skelette.' All Zita could comprehend from all of that was that her mother killed her father, and she never forgave her for it.
Unable to bear the scorn of her beloved daughter, Eva fled, leaving Zita alone to fend for herself. She ended up coming across Shinra, who was sent to kill her. As he was about to slay her where she stood, he found a trace of the light he knew to be the heritage of the original Grimnis within her and captivated Shinra's heart, since he was the physical embodiment the original Shinsei, who was fully in love with Shinrei, who was also Grimnis. Their union thus created the forbidden child, Khrona Tensei, a Grim that harbored a pure soul of his own, overpowering the use for magic, even though it was capable. Before he was a year old, however, Eva's darkness grew more within her and started to consume her more and more. She wished to keep herself intact without being consumed by the Insanity as well as her Devourist heritage, causing her to split herself into two halves known as Parace and Evangeline. Where Parace was all of Eva's remaining light, Evangeline was all of her darkness, and so the same history as what happened with Tensei had started all over again with her. Eventually, Shinra caught up to Parace, who was Eva's light, and instantly knew it was her. Meanwhile, elsewhere, Evangeline had gotten back with Rowan, who she felt would spawn her the perfect child to complete her father, Grimlock's work. Whilst Parace stayed with Shinra, Evangeline bore Rowan's son, Maze Rituke, a being born with inherent powers of magic that rivaled the Witches, and also a soul that would not fall to the Devourism. She was pleased with this child, however, the magic within him was quite powerful, and he would be a possible candidate for falling to the Sway of Magic.
Evangeline, finally fully understanding her father's work once she split herself, wanted to continue on his path of relieving her heritage of this Devourist curse. Because of this, she figured that both Maze and Khrona would be her 'Perfect Children' that would use the power of Magic without falling to the Sway (Maze) and could be a Grim that harbored a soul and Insanity without being consumed (Khrona.) Once Shinigami found out about this, he was beyond furious, and ordered Shinra to kill Evangeline by any means necessary. Evangeline found her only escape to be the Cauldron, and so she took Maze and Khrona, her perfect children, and hopped into the Cauldron. Knowing that there was no way to track her down once she was there, Parace insisted on going after her, since both halves would have to meet up in the same world and become a whole again. With a sad parting, Shinra parted with his family, and Parace hopped into the Cauldron as well, following Evangeline and her children. As a result, they traveled many centuries into the future, to the realm of the present day. Because Parace held the curse of the Tensei, she eventually lost sight of her own form, being trapped in the Cauldron as the 'Forgotten One.'
When they emerged, Khrona ended up on the other side of the isolated reality whilst Maze and Evangeline on the other, though Evangeline felt the faint presence of Khrona somewhere on this plane. Creating an establishment for Maze, she would teach him from afar how to use his magic, whilst Khrona grew up completely alone, letting his powers fester and grow into his own reality in his head. And that was how the two grew.