It was a sword set stabbed deeply in stone, just like a particular old english legend.
A legend where a man, no more than a peasant pulled a sword from a rock and became a monarch.

'How original of a story.' Rei scoffed at the idea.

Although it was by all means such a stupid and unoriginal plot, Rei had no choice but to agree with what she was going to do next.

"What a fitting tale." Rei said, her red eyes glowing coldly in accordance to the light of the full moon, her expression unwavering.

She turned around, to see what she did while she was moving unconsciously while dreaming, and sure enough there was a lot of damage.
Prisician palace guards...or what used to be Priscian palace guard lay motionless on the cold stone floor of the altar chamber where the Essence of Gluttony stood.
A few splatters of red liquid dyed the floor on some cracks. It oddly smelled like rusted iron and sulfur. It was obviously the smell of human blood.
Some of the corpses necks and other bones were bent the wrong way, some of their torso or head parts were even caved in, The armour didn't help at all to reduce the damage dealt. Some of the corpses' helmets had blood dripping down from them, the sign of accurately stabbing between the gaps with a knife, or maybe it was due to them coughing or vomiting blood and their lunch after having their stomachs caved in.

Rei stared at her left hand, which was holding a bloodied knife, and then her right hand which was also covered in blood, indeed this was the result of her moving unconsciously.
Rei brushed the problem off, promising to herself that she would find a solution later and returned her attention to the sword stabbed deep into the rock.
Rather than a sword, it would actually be much more accurate to call it a pulsating rod, For not only did it not have a handle, but an edge to the 'blade' was nowhere to be seen, thus making it 'non-existent'.
It would seem like a useless object considering it's external appearance, however Rei felt the sword calling out to her, lynching her in as if telling her to go grab it, 'Use me and devour everything' is what it seemed to be saying to her.

The Essence of Gluttony wanted to satisfy its hunger.

'Maybe it is my destiny' Rei thought.

It was in the nature of Rei to be cautious, think everything through before doing anything you do. That was one belief she stuck to.
However even though it was the first time...

"Let's devour everything then." Rei said, her hand reaching towards the Essence of Gluttony.

It was the inarguably the most careless decision that Rei made throughout her life...
The Essence of Gluttony changed its form of matter, transforming from a solid into a bonafide almost-geniune liquid, as soon as Rei even made skin contact with the rod, the rod slithered up to her skin, seeping through her skin, it was like being injected with needles.

And paired with Rei's blood curdling screams, the merging had already begun.

The proud 2nd Princess of the Kingdom of Priscia.
Listicia Priscia, age 19 is the 1st child of the King's 1st affair.
Whenever she was seen by her older siblings they would look at her in disgust, being reminded of their father's unfaithfulness.
Even the servants looked down on her when she was at a young age, they considered the yellow hair who Listicia inherited from her mother to be unsightly and an abomination, they tormented her day and night.
She was first intended to be disposed of to prevent a royal scandal, however being told by the former Priscian Oracle that Listicia was born with a special ability the order was quickly pulled back at a frightening speed.
She had the skill [Oracle] which let her see the past and a far end of the future of anyone she touches.
Thus, with this ability she was welcomed into the castle, her older siblings who used to ignore her when she was suffering quickly changed attitude, and the servants of the palace who insulted her were now trying to curry favour with her through flattery.
It really was a very quick change.
Listicia was made to see the future of high nobles and other important people from other countries on a regular basis, because of her ability the Kingdom of Priscia had managed to win many wars, and avoided many disasters so far.
However one day she saw it.
While seeing through her future for the first time, she saw a Great War a few years into the future, it devestated every corner of the continent...and the ringleader of it was...a figure in black...a Demon Lord swallowed the human kingdoms one by one, her army of monsters and demons trampling on all life, desecrating everything on sight, Listicia called it an 'unavoidable calamity' that could not be solved by any of this world's military assets.
Not even the Void King Estel could stop it.
So she proposed an idea to the king.

'10,000 years ago, the former Great Demon Lord was defeated by the 7 heroes, it consisted of the 7 representatives of the brave races. The representatives of humanity was a human not from our world.'
'Not from this world...you say?'
'Yes, and according to the records, it was written that the summoned hero quickly mastered the use of mana, and was the founder of the 7 heroes.'=
'You mean the Great Heroes Seo Yoon-Hwa and Takahashi Kira were summoned from another world!?'
'Precisely father, so here is what I am proposing.'
'Go on, I'm listening...'
'The future I saw is a few years from now, so here is my idea, let's summon the heroes beforehand and have them level up before the Great War begins.'

If nothing in our world can stop it, then we could bring in something not from our world to solve it for us. That was basically the idea.

That idea was quickly accepted. However even if they knew it beforehand, the summoning ritual required years of stored mana to summon a single hero, and after they did they could no longer summon a hero for about 1,000 years because space would disfunction during that time period.
2 years worth of mana could only summon 1 hero, so they made sure to double the amount of summoned heroes to make it worthwile.
8 years worth of mana was saved, and 8 years quickly passed until the promised day.

The Four...five heroes were summoned inside the heart of the Priscian Kingdom...the Priscian royal castle.
At first Listicia and the King were quite perplexed, they prepared enough accomodations for only 4 heroes, so after talking it out, they would let the heroes explore castle with knights disguised as squires and sent the order quickly.

Once the initial introductions were done, Listicia reached out her hand to shake the hand of the most eye-catching hero...She said Yuusha was her name and Listicia believed it sincerely although it was a name that would seem out of place in this world.

'It is alright, the names of the first heroes were pretty weird too.' Listicia thought as she shook Yuusha's hand.
It was at that moment that her ability to predict the future struck her like a bullet.
Fierce and severe pain assaulted Listicia's body, making her faint as she saw not only the future of Yuusha but also her dark past.

Yuusha..or rather Rei's future exactly matched with the vision Listicia saw 8 years ago, Listicia saw Rei's figure standing atop of a mountain piled up with the corpses of every race. Rei was the Demon Lord who was responsible for the burning future. And not only that, but Listicia saw Rei's past.

Rei killed each and every one of her first friends, and slaughtered all the people who raised her. That was the summary of what she saw, although what Listicia saw in Rei's past was very little, that alone was enough.

'She's not even human, demon, or a monster, she's a mistake.'

'She's a vile thing wearing human skin, it should not be allowed to exist.'

The summoning magic that was used to summon souls from another world. One soul that was summoned from Earth needed 2 years worth of mana, nothing less, if even the tiniest speck of mana was missing, the summoned 'hero' could already be dead before they arrive to this world.

A soul is the proof that a creature lives, it is believed that all living creatures have it, be they human, demon, monster, or animal. It is proof that they were born through an ancestor.
In human terms, it means parents, or the natural means of birthing.

8 years of mana granted four soul tickets, only 4 heroes were supposed to have arrived.
However 5 heroes came, what did this mean?
It meant that one of them...Rei was not a living thing, a vessel without a soul.

A mistake...A huge torrent of evil that was dragged along, that's what Rei was.

Over the course of one night, Listicia's view of Rei changed completely.

Listicia woke up with a haggard expression, it's the most tired she's ever looked, and sleep is supposed to get rid of fatigue.
Listicia scouted her surroundings, without a need to say, she was inside her own room.
A bedroom truly fit for royalty, she slept at a fluffy bed that could fit a family of four with ease and still have some room left over for the family dog. A large mirror at the side of her room was hanged, obviously so she could have no issue when letting her personal servants attend to her appearance.
The carpet the floor was covered with consisted entirely of the finest wool, which sheep farmers would shed blood, sweat, and tears just to produce a steady supply for it every year.
The other side of her bedroom held a stained glass door to the balcony, the moonlight flowed in with a slightly more whiter colour, it's light having been affected by shining through the magic stained glass.
However Listicia was already used to this, and took her luxuries for granted, however when she woke up she once again cherished her possessions, for just from her drean alone, which made her see the future in which she possessed nothing made her treasure everything she ever owned.

Staring into the stained glass which thoroughly depicted the night city, Listicia's father Lambert said to her.

"Listicia."
"...Father."
"What did you see?"

Listicia didn't answer, no....she couldn't answer, how could she tell her father that the hero they thought they were going to save them was actually responsible for the future wherein they, and everyone they cherished all died?

Guilt welled up within her, and silenced her as well.
Listicia didn't say anything, however from Listicia's pale and grim expression alone Lambert could already tell.

"Wallace."
"Yes my liege?"

At that moment, a butler which had been silently staring at the situation spoke after being called out.
The Priscian palace butlers were so good at blending in with the environment they could actually build a career on the game hide and seek.

"You know what to do." Lambert said coldly.
"Yes...my liege." and the butler Wallace replied indifferently, afterwards exiting the room, carrying his rather vague orders.

"O Goddess...please have mercy on us."

Just before Listicia woke up, and the castle guard was alerted, a certain grey-haired knight...Ursus stared at a certain corpse inside the royal library.

'Henry...you had such a bright future ahead of you...'

The corpse, formerly Henry lied motionlessly on the floor of the royal library, his blood smeared the floor and his eyes which were unfocused seemed to be looking straight at Ursus as if saying 'Why didn't you protect me? You said you would make me into a great knight didn't you? Was that all just a lie?'

Henry did indeed have a bright future ahead of him, being Level 5 at that age meant that he had promising talent as a knight, even surpassing the palace guards....yet he died in a ditch, inside the royal palace no less, and Ursus couldn't have been more enraged at this fact, as everything he taught his squire, everything he had cultivated was now nothing more than a dead and cold piece of flesh.

"I'm so sorry Henry..."

Ursus gripped the handle of his sheathed rapier, almost damaging it, his eyes burned with the expression of fury for his murdered squire.
Ursus stared at the trail of bodies leading inside the royal library's hidden passage, Ursus kicked the ground and ran at full speed following the path of the blood of his comrades in arms.
With tears flowing down his eyes, Ursus shouted with his heart which felt as heavy as lead.

"I'LL DEFINITELY AVENGE YOU!"