*
They all stood straight, good as new with perfectly healed bodies without a single blemish.
Round 2 perhaps, landing from above, Hikari strikes downwards with her arm, putting her full elbow into it. Like a spring winding up and releasing its tension, she pushes her body to move even better. Alter returns her attack with her own strike, a large shock wave arising from their clash slices across the castle behind them. Alter throws another strike, perfectly hitting Hikari's knuckles, then Aevilli's as she fought both of them by herself. For some reason she was able to deal with each and every strike thrown by the 2 in a tag team, unleashing countless shock waves that annhiliated the surroundings. Despite the castle being made of antimagic, it still suffered quite the damage since Aevilli's shadow doesn't have infinite stats like her true body did.
A fist encloses onto Hikari's face but was blocked by Aevilli in time. Aevilli resumed her momentum without pause, throwing her other fist after blocking the first punch. Hikari herself had rearranged her own position, stepping behind Alter's back to launch another flurry of punches. The first few were blocked, then the next went through. They both needed to give their all of they wanted to overwhelm Alter, they can't team up and only send out the output of a single person fighting, they had to make use of their numbers and fight well enough to beat a single person instead of reaching a stalemate.
Hikari sends a high kick, Alter dodges and closes the distance, she comes too close and couldn't land a hit so she uses her bicep to directly lift and throw Hikari. She swings her left arm, slamming the back of her palm on Aevilli's punches, then lifts her leg up for a high kick with the same momentum. Like a springboard, her leg shot into the air and blew away Aevilli's right arm, Aevillie exploited the chance and slams her left fist into Alter's leg, bruising it heavily. Alter leaps away, her injury healing in an instant. Hikari arrives to launch another volley of punches.
Matching fist for fist, Aevilli interjects in the same moment, landing a hard blow into Alter. Alter uses [Heavens breach the destiny's core] and shifts reality so that she never took any damage.
"... Fine. Divine demonic transgression, world order disaster entity supported. [Demon King existence materialisation], release Aevilli" (Hikari alternative)
A black hole appears in the space next to her, what could only be described as black lightning flashed from the ends of the universe and into the hole, as if it was bringing forth an ancient evil... Well, she wasn't old enough to be considered ancient but she did exceed the human lifespan along with the current Demon King. Aevilli as the castle is a crucial aspect of the Demon King's existence as a whole, while Hikari is the main body that bears the title of the Demon King. It might include far more entities and abilities under its purview, even Hikari wouldn't be able to assuredly uncover everything there is in the existence known as the Demon King.
The Aevilli's began to fight each other, matching move after move, before long they managed to wore each other down and concluded in mutual destruction.
"... I'll take care of you myself, at this stage my castle wouldn't help much, would it?" (Hikari)
"Your resolve will be extinguished, I will have your inferiority demonstrated before your very eyes." (Hikari alternative)
Their figures vanished, only appearing reflected in the iris of the other, each strike they throw is countered by another. At this moment they were both engulfed by their own battle highs, drowning in exhilarating adrenaline. Alter slipped past Hikari and lands her fist onto her cheek, Hikari manages to do the same without Alter noticing that she had allowed Alter to get close in the first place. Their fists land on each other's cheeks, blasting the other party far into the air behind them.
Spinning to quell the momentum assaulting their bodies, they leapt back to their initial position with a single step, Hikari throws a right hook that was easily dodged. Alter side steps to her own left into Hikari's blind spot and throws her right fist. Hikari couldn't dodge in time, so she pulls back her right fist and intercepts with the body of her arm. Her flesh splits apart and her skin is burnt, tendons and nerved fray into the air separated from her arm bones like loose fried meat.
Hikari turns her gaze to Alter, her eyes hadn't flinched one bit, her resolve was clear for all to see, it would never break down ever again. Not even defeat from Kaori would leave lasting marks on her ego, as the strongest Demon King in history that could rely on nothing but herself to defeat God magical girls, she cannot shy away from even a single challenge. Everything that dares to bear their fangs against her will properly face her due wrath, all of her will, body and soul unites into her steadfast existence.
Alter could only sigh silently as she gazed at Hikari's vain attempts. Did the imitation really believed that she could defeat the original? Hikari's [Disaster] was an imitation of Alter's, even if it was the zenith of her life's potential and destiny, or precisely because the summit of her capability is but a mere imitation, she would never be able to defeat the genuine article. The biggest difference between imitations and originals is the magical phenomenon behind their respective skills. An imitation would try to simulate every effect, every colour, every texture and feel of the original to the point of perfection.
Sure, they become the complete same on the outside, but the core mechanic of their existence would be different. For example, an original fire magic might provide the oxygen and spark to light up the fire created in the magic. An imitation would recreate the fire's flickering light and capability to burn targets, but it wouldn't need oxygen to continue burning nor would it produce heat. It only imitates the effect of burning without using the underlying mechanic of combustion.
While something as simple as fire would be an unapt analogy, as matters become more arcane and abstract, the original magic would have far more different effects that the imitation cannot recreate. In other words, Hikari's [Disaster] works to reenact The Great Disaster while Alter's employs the true principle behind [Disaster], however Hikari had also awakened her own [Disaster] into something that was genuine and original in its own right, it had become [The Great Disaster(True Awakened)]. It now operated under its own principles that might run contrary to Alter's [Disaster] despite sharing similar results and looks.
Through her own resolve, Hikari understood what it meant for her to be a disaster. An undesired state for the rest of the world, pushing someone's buttons, overturning the laws or mocking the resolve of the world. No matter the enemy, there was always something they wouldn't like. Hikari wonders, what is Alter's bad end state?
What was Alter's desired state of everything that exists? What did she so desperately wanted to protect? Why was she fighting? Hikari herself fought to revive demonkind, she was ready to abandon herself and defeat the other God magical girls should it be necessary. So what was the key difference between them? Is it their past... Or their future?
Hikari brings her right palm up, her fingers squished up into a knife shape that flowed gently through the air, one swing and it smashes against Alter's knuckles, another swing and Alter was being pushed back. Of course she was accurately receiving all the attacks, but the force behind each hit was powerful enough that they released all their energy onto Alter and physically pushed her back a bit. They both leapt into the air, Hikari spun and slammed her leg onto Alter who returns a kick in kind.
This time they separated and joined back in another clash, this repeated a few times until they've exchanged multiple nonsensical blows. Clashing their left arms once, Hikari moves closer and pulls back her right arm for a punch. Before Hikari threw her fist out, Alter swings one of her arms and intercepts. Their arms rub against one another like screeching steel, pushing one another backward gradually. They struggle in this stalemate until Alter pivots on one leg and swings the other to execute an abdomen kick.
Hikari tanks the hit and slides back gradually, their bodies heal in an instant as they maintained their gaze on each other now. That was the gaze of a hungry animal ready to devour anything that was fed to it. They close the distance once more, Alter shoots a forward kick that was dodged before throwing multiple punches. At first Alter wanted to find an opportunity to bring Hikari's guard down, but since there's no chance, she was ready to fight directly to wear down her opponent. Hikari catches the barrage of punches and leaps even closer to Alter, striking a headbutt onto Alter's forehead and dealing damage.
Some blood slipped from her lips as she observed her attacker with clarity. Pivoting with one leg, Alter swings the other leg with great force, shattering the bones inside Hikari's right leg which rose in that moment to protect the rest of her body. With light steps, the distance closed before anyone blinked and Alter was going in for another assault. Deflecting Hikari's right arm twice with her own, Alter slams her fist into Hikari's chest, sending her flying into the air. Her figure vanished and she reappeared behind the flying Hikari, melding her fingers together she slammed a ball of her fists into Hikari's back.
In an instant, she threw 5 punches and 4 kicks, beating Hikari into a bloody pulp on the floor before her. [Heavens breach the destiny's core], reality alteration allowed for Hikari to ignore the entire past sequences of assault that she received. Her body was now perfectly fine as she stood upright, facing off against Alter once more. She wonders how many more times must they exchange fists. With each impact, Hikari could feel her knuckles and arm flesh soar into greater heights. Her skill and ability was actively improving the entire time.
She pulls her arms up, blocking punches and throwing them. Her arms pull up to cover her face and tanks two of Alter's punches before pushing further in, Hikari then throws a kick onto Alter's torso which sends her flying. Her silhouette vanishes from the far off distance she was thrown to, she lands behind Hikari while sending out a powerful jab with her left arm into her back. Hikari was sent flying but also returns immediately. She throws a couple punches which were both avoided before side stepping backwards to avoid Alter's hooks. She steps forward and throws a few more punches, each time her knuckles were caught in Alter's palms.
Alter lifts a knee for a kick, but another knee slams into hers, preventing her from lifting her knee up. She uses [Heavens breach the destiny's core] to reappear right above Alter and threw her strongest magic.
"[The Great Disaster(True Awakened)]!" (Hikari)
Reddish black light flew from her palms to swallow Alter in a deluge, causing her skin to wither and bones to melt as her body breaks down. Her augmentations malfunction due to [Disaster]'s effects and her death was in a matter of moments... [Disaster] was the conjuring of an undesirable state, or at least that was the case for Hikari. But for Alter...
Originally, [Disaster] was a corrective force brought about by the earth as a measure against humanity's overconsumption of resources. But all [Disaster] stemmed from Alter here, who was the progenitor of all [Disaster] across every universe. At the same time, it meant that as long as disasters continue to naturally exist, so too will Hikari alternative.
Getting closer to the truth, the earth borrowed [Disaster] from Hikari alternative via the book of akasha... While normal librarians cannot access skills exclusive to God magical girls, the earth was able to recreate any phenomena that has once existed and will exist on the earth's surface, meaning that even God magical girls are under that rule and their skills can thus be recreated by the earth. In other words, even if Alter is in an undesirable state... She will continue to persist as a natural force to be feared and revered.
Since ancient times people have payed respects to natural disasters, citing them as God's wrath and dissatisfaction. So the true nature of Alter's [Disaster] is divine correction meant to curb human ambition, an anti-humanity and Idealism magic. One befitting the regality of the ruler of demonkind.