In the present -
Arthur looked at the Demon in front of him with ridicule. A residence of Hell which he got dominion over, or will have dominion over once the ability Hell's Messiah fully kicked in. For now, all he could do was restrain this low-level Demon, but it was enough. He didn't have any plan to let it live much longer anyway. 'Once I bathe in Hell's energy, I'll be able to bring out its full potential.' The very thought of his plentiful harvest made Arthur ecstatic beyond measure. Unfortunately, now is not the time, he's too weak to pass through the gate.
"W-Wagh.. Ab.. u-U DagHH!!! (What Have You Done!!!)" The Demon fearfully yet at the same time angrily screamed. It tried to control Arthur through the link, but it was useless. It tried to detonate the link, but it was also useless. The river-like connection that was flowing towards the Demon's direction suddenly changed course. The current was reversed and with it the Demon's powers.
Using Hell's Messiah, Arthur gained control over the link, and he used it like a straw to suck in the Demon's power.
"Whaagh Ayy?!! (Why?!!)" The Demon asked as it felt more enraged at the very thought that it was betrayed by a weak looking human.
"A contract with you? HAHAHAHA" Arthur understood the Demon's feelings and didn't hide his disdain.
A mere pawn wants to forge a contract with me. Laughable. Arthur smiled like a maniac. A Demon will never make an equal contract unless its life was on the line, this little Demon wanted Arthur to be its servant in exchange for a little bit of power. It would then harvest Arthur's soul after being corrupted to the fullest by demonic power.
There would actually be conditions and rules at the beginning before a contract was made. In that contains the terms both sides had to agree on before proceeding to make it official. There's also one constant condition that every Demon puts on the table, and that is demanding servitude. That is how it usually goes but…
The Demon thought it managed to trick Arthur since he didn't present any condition. And since it felt like it was more powerful than Arthur, the Demon thought dominating Arthur's mind seemed easy.
The Demon skipped the procedures and made Arthur sign the contract immediately. But unfortunately for the Demon, Arthur actually preferred it that way since it would be faster, and he wouldn't have to endure the pain of soul branding longer.
"HUMAAAA Dergh!!! (Human you dare!) " The enraged Demon poured heavy pressure onto Arthur. It might not be able to move but it still managed to bring out some of its power. Tentacle-like tendrils sprang forth from its body intending to skewer Arthur.
Arthur side steps, ducks and even rolls on the floor to evade the attacks while inching closer to the Demon. His body moved as he wished but even so, his body was still untrained and had been weak for years so there's some gaps in his movements.
Some of the tendrils managed to scrape his skin and some managed to bore a hole through his thighs and stomach. Nonetheless Arthur continued to move forward while cutting the tendrils with his sharp nails. The hit should've been fatal, but his blood came rushing back to his wounds and it healed instantly. Although it seemed like nothing would harm him, Arthur was actually depleting his endurance at a rapid pace. If this goes on much longer, fatigue will catch up to him leaving him vulnerable. He would also revert back to his normal form which would weaken him greatly. But despite everything Arthur laughed louder and enjoyed the power the demon was showering him with, even while puking blood as he got skewered on the stomach.
His Devil Origin Physique was able to negate the little bit of power the Demon managed to bring out. Although it hurts since it was intended to harm him, he still managed to negate some of it. Arthur was simply the bane of all demons. His power was made to suppress and dominate all those that resides in Hell.
"MOOORE! Give me more!" the more power the Demon uses, the more it will become powerless.
With a leap, Arthur arrived in front of the demon. His thin fingers got a hold of its flesh. His nails buried itself deep before a mysterious power sprang forth and rained down on the Demon. The Demon slammed to the floor, face planting as its eye quivered in fear. After making contact, Arthur managed to apply more pressure on his meal. Like a half-asleep Dragon pressing down on a Lion. No matter how ferocious the Lion might be, it would still be nothing compared to a monstrous Dragon.
The Demon felt primordial fear towards its opponent, and so it didn't take long for it to panic. "It was a mistake manifesting in this world, little Demon."
Manifesting in another realm will always have some restrictions to those who don't belong in that realm. Not unless it had a vessel to possess. The Demon thought Arthur was a devout Demonic follower who worships Demons because of how he perfectly performed the ritual, but everything was actually just an act. With its little ability to think, the Demon greatly felt regret.
Normally Demons would be too cautious to manifest their real body in other worlds since it wasn't their turf. Experienced Demons would only send an avatar to forge a contract. Arthur knew that only weak and desperate newborn Demons would flock toward a single human soul. After all, to summon a high-level Demon one would need thousands of souls. There was also the quality.
"Kuhahaha newborns are so naive!" exclaimed Arthur and soon began munching on the demon's body. He bit and tore its body bit by bit.
The taste couldn't have been nastier but the feeling of gaining power made it worth it. Using Hell's Messiah, he absorbed the Demon's power as well as its very being. His Devil Origin Physique managed to become a bit stronger in the process as if it was gaining a little bit of its origin. If he wanted, Arthur could do this again and just keep on farming low level demons until he became powerful enough to hunt high level ones, unfortunately absorbing too much demonic power is the same as announcing that he was Demon follower.
He would fall under the radar of the Garden since concealing such dense demonic power was impossible. The malevolent power was something unique to Hell and it should belong in Hell. It was different from the Aera that could be found in this world. powerful mages would be able to sense his Demonic power from miles away if he accumulated too much.
The Demon cried tears of blood, being eaten alive was a humiliating and horrific way to die for a Demon who prides themselves as evil creatures. The pitiful thing could only roar in pain and fear as it got devoured.
Arthur's Vampiric body benefitted greatly from the Demon blood he consumed. The demonic power in him also continued to bloom like a flower, his body accepted everything!
As he was eating the Demon, his body underwent another metamorphosis. He grew a black tail with a sharp blade like bone protruding at the tip as well as two black curved in his forehead. His sclera turned pitch black making his eyes look more demonic and menacing. The nails on his fingers and toes also turned black as if dyed by ink. His Vampiric form has evolved and the darkness element he harnesses has become more powerful. Added to his element was that of Fire, specifically Hell's Fire. A corrosive fire element that not only burns but also rots and inflicts more pain.
Arthur ate the demon in fifteen minutes, and he wanted more… Unfortunately, he already reached his limit. Too much power up will only add more time for him to get use to his powers. A luxury he didn't have.
If Arthur had a character interface it would look like this -
[Name: Arthur Severus Rory]
[Age: 16]
[Race: Human, Vampire (Baron Class) Devil (Newborn)]
[Innate Physique: Unknown]
[Acquired Physique: Primordial Vampire Physique (Half-Awakened/Primordial Rank) (Element: Darkness) (Core Ability: Blood Dominion)]
[Sub-Category: Ability]
[Blood Dominion: The ability to feel, control and transmute blood. Abilities includes infrared vision, regeneration and bloodlust] (Ability's power depends on how powerful the user is)
—--
[Acquired Physique: Devil Origin Physique (Celestial Rank/Half-Awakened) (Elements: Fire and Darkness) (Ability: Hell's Messiah)]
[Sub-Category: Ability]
[Hell's Messiah: The ability to influence or dominate any sentient life (works best on Hell's Residents). Abilities include mind break, corruption and temptation.] (Ability's power depends on how powerful the user is)
Arthur had specifically chosen these two physiques to unlock since he had the necessary ingredients or means to awaken them.
'This should be enough to kickstart that Physique in a month.' The youth clenched his fist as profane hunger started manifesting inside him. And as Arthur was thinking about his next step…
Another gate appeared…
From it came another demon. It was nothing like the demon he ate earlier. It had the appearance of a pale old lady. 'Ooh a rare Demon Banshee, perfect!' Arthur exclaimed in his as he kneeled and expressed his servitude.
Banshees like women sacrifice the most, too bad it's the other way around as the same scene played out, the only exception is that he didn't eat the Banshee this time. Arthur used Hell's Messiah to immobilise the Demon and he was able to do it much faster this time after using the demonic power he had absorbed earlier.
—--
The fog dispersed showing Arthur and Dian's corpse. Arthur was no longer the demonic being that he was; he was back into being a frail weakling, only in appearance that is. He dispersed the remaining miasma along with the blood splattered across the floor. He then walked toward Dian's slightly cold body. He bent down and inserted a black mass into her open chest cavity.
The black mass was the core of the Banshee. After dominating the Banshee, Arthur destroyed its will and absorbed its power. He left the core untouched and removed all the unnecessary impurities from it. What remained was a clump of pure demonic energy. After performing some hand gestures, he wielded Aera. The magic circle below glowed brightly before dissipating but it didn't take long before a new magic circle appeared and replaced it… it was the first magic circle he drew.
Dian's corpse was only to lure some newborn demons or low-level ones. It was never his intention to sacrifice her. He had another plan for her. "You might hate me for this but it's alright. I will accept that hate as long as you gain the freedom and power you deserve."
Arthur wielded the new magic circle and as if coming to life, it floated and wriggled. The runes were like worms while the rest of the designs were like veins pulsating in dark red color. It shrank little by little before descending down onto Dian's body. It engraved itself in her skin making an ancient looking tattoo that covered her entire body. The tattoo glowed and soon dark tendrils sprang out from her opened chest cavity. The tendrils wrapped around the black mass that Arthur inserted in. The black mass was molded by the tendrils and soon turned into the shape of a heart, a human heart. The size and appearance were the same as that which was previously dug out by Arthur. The heart was not physical so any physical damage or illness for the heart won't affect it. Unless it's holy power then nothing will stop this heart from beating.
Arthur was very careful and precise with the operation. Like he had done this countless times before. This practice was one of the unholy taboos, one of the experiments that the Garden absolutely abhorred called Infernal Transmutation. If found out not only Arthur and Dian would suffer, but the Garden will also wage war on the Rory Household, and they won't stop until the Rory bloodline is eradicated. This is the magnitude of what Arthur had carried out.
He learned this practice when he infiltrated a Cult in his previous life. He actually prefers this method instead of making a contract with a Demon since not only will you gain power, there's also no Soul Branding. Unfortunately, you still need a Demon's help to make this work, more specifically, this method needs Demonic Blood to kickstart the organ. Even in the cult, this practice was uncommon since those who underwent this surgery always lost their rationality and were short lived. Their body decays overtime since demon blood is full of impurities and is essentially a lethal poison to a human body. A flaw that Arthur had solved.
One simply needs to use a Devil's Blood, instead of a Demon's to kickstart the organ in question. This solution was something he discovered after he awakened the Devil Origin Physique. It was just one of his experiments to fully understand what his body was capable of.
For a normal human it was that simple, you only need a Devil's blood to complete the procedure. It was simple yet the accomplishment of the task was impossible. Since getting a drop of blood from a Devil is like counting all of the stars in the universe. It's simply hopeless.
Devil's act like royalties, they're arrogant and prideful, it was their nature. And they were born with the ability to back such disdain for the common. No Devil in their right mind would ever give their blood to a human. They might form a contract with one but that's it. Just the very thought of giving their blood to a lowly human might make them cough blood.
Now although he's not a full-fledged Devil yet, Arthur already had the blood of a Devil flowing in his veins when his Devil Origin Physique manifested. His blood was more than enough to enable Dian's demonic heart to beat and function.
Why did Arthur eat her heart in the first place? Some may ask.
Firstly, Arthur wanted Dian to become powerful. She was an ally he absolutely needed. Obviously it's impossible for Dian to escape soul branding so forming a contract with a Demon is out of the question. She also can't form a contract with Arthur since he wasn't a full fledged Devil yet. Arthur could turn her into a Vampire but he won't have the necessary power to fight a Demon. He needed a boost.
That brings the second reason he ate her heart. It was necessary, it was the most efficient way to show that he had a demonic nature, to be more convincing and attract a Demon faster. It also served another purpose, to strengthen his Vampire Physique. Eating a heart gives him more fuel than just drinking blood. And that fuel greatly helped him in contesting with the first Demon. With all of those things in the equation, Arthur managed to not only gain one but two powerful physiques. Although half awakened, it won't be for long. These two would be the core Physique he would focus on.
After the heart was fixed and connected, Arthur dropped some of his blood onto the black heart, and like an oiled machine it soon pumped like a normal heart. Dian's red blood soon took a darker shade, and her organs began functioning once again.
Demonic power oozed out of the heart which closed the gaping wound on her chest. It also started healing all of her wounds. It even began curing her scarred face which won't do so Arthur stopped it using a mental connection. His blood was the one that kick started her black heart after all.
Dian was no longer a human being. She was much more, someone that could transcend a mortal status.
She will wake up with her memories intact, but she will never be the same. She will be forever bound to Arthur, after all, his blood is what's keeping her alive.
After everything was done Arthur carried Dian's body to the bed and proceeded to cover her body with bandages to hide her already healed body. Then finally, he clothed her.
After double checking if all the bloodstains and Aera residues were gone, Arthur modified the runes a bit, making it lose its effect but nonetheless, the original designs were still intact, and he could fix it simply by using Aera to restore back to its original state.
After everything was done, Arthur lied next to Dian in bed as the dome of invisibility collapsed.