Dragon's Heart

(Mio's POV)

Something isn't right.

A few years ago, we made a contract with the Five Principal Clans to stay here in Tokyo and make contracts with people here in exchange for us to eliminate the Strays around Tokyo.

And the Stray Devil that we were supposed to eliminate a few days ago was already dead when we arrived at the local. Although it in itself isn't strange considering that it could be eliminated by an exorcist passing by or something like that, Zest, who is a former Youkai and skilled using Senjutsu, said that she sensed a strong dragon scent in the abandoned building.

That means either a dragon eliminated the Stray Devil or someone with dragon-related sacred gear.

The first one is improbable as most of the dragons are currently living in the Underworld and there is no reason for them to be here in the human world. So it was probably a sacred gear user and if it is like what Maria said, it will be a high-tear sacred gear, even a Longinus probably.

*Sigh*

'Why do I feel that this is going to get more complicated?' I complained in my head as I felt the uneasy sensation on my chest.

*Knock* Knock*

"Come in," I said as I looked at the door.

The door opened and my maid bunny knight entered.

"Pardon for my intrusion, Mio-sama" She bowed slightly after she closed the door behind her.

"It's fine," I said with a sweatdrop as she acted the same as Grayfia when she was with Onii-sama at work, "So did you find something Zest?"

"Unfortunately, we haven't found anything yet, Mio-sama, but..." I was a little disappointed when I heard that she didn't find anything, but she immediately caught my attention in the last part.

"But?"

Zest then walked towards me with papers in her hand and handed them over to me.

"This is…?" I asked as I opened the folder.

"This is what we found about the boy who Astaroth-sama seemed to be interested in" Zest answered and I widened my eyes.

Lars Astaroth, the current heir of the Astaroth clan and just like me, is the brother of one of the Maou, Ajuka Beelzebub and not only that, it is said that his intelligence is comparable to his brother, who is known for being the genius of the Underworld, and for unknown reasons, he came to the same school as me, a completely normal school.

And, despite being in similar situations, we only talked a few times and could only be described as acquaintances, but still, I would check up on him from time to time to monitor him, but I always found Lars alone.

But this year was different, Lars seemed to be interested in one of his classmates, and for him to be interested in someone, that said person couldn't be a normal one.

(A/N: Not that kind of "interest"...)

"Kotomine Shirou, 16 years old, staying in Sakurasou Dormitory..." I began reading his file and widened my eyes.

"An orphan raised by Kotomine Risei, who was one of the strongest exorcists before retiring and died due to old age and also suspected to have a powerful sacred gear..." I muttered in surprise.

"What should we do, Mio-sama?" Zest asked.

*Sigh*

"We won't do anything, for now, as long as he isn't endangering us we will stay neutral," I said while shaking my head.

"Do you think he was the one who killed the Stray, Zest?"

"I don't know Mio-sama, I have to see him in the person to make sure, but the possibility is very high"

"I see…" I replied as I got up from my seat. "Let's go Zest. We should get going or else we might be late for the classes"

"Understood Mio-sama, I will make the preparations right away" Zest bowed and left the room.

(3rd POV)

Meanwhile, Shirou was flying above the clouds in his Balance Breaker form.

Shirou hypnotised Chihiro and everyone in the Sakurasou to let him skip school because he "caught" a cold and needed rest.

Shirou would love to do this more times, but he was sure that would only cause more complications to his life in the future.

"Are you sure about this Shirou?" Albion asked through the wings. "Although I am not against it, in fact, I even support this, but doing this right now will only make everyone wary of you."

"I know," Shirou replied, "But if I don't do this now, I don't know if I can be strong enough to eliminate future threats."

It was a known fact that Shirou shared with chat group members that the moment you awaken your Device (weapons that manifest from the soul of the individual), you would be tied by the chains of fate and you can't raise your mana reserves by normal means.

But in a case like Kuroneko, who wasn't born with mana, Shirou theorizes that she will awaken her mana reserves after she unlocks her Device.

Regardless, it was still the fact that it limited the growth, which is what Shirou wanted to avoid happening.

There were only two ways that Shirou knew at the moment to solve this problem.

One way is buying an ability from the Dimensional Shop to break the chains or to raise their mana reserves by spending coins.

And the other was the normal way, train until reach the bottleneck of the potential, and then break the chains of fate upon "Awakening ".

To achieve the "Awakening", it is carrying one's potential as Blazer to the absolute limit and it also needs a will to ascend even higher, which will result in the strengthening of the soul.

"Hey, Albion" Shirou called the Vanishing Dragon, "What about the curse?"

"You don't have to worry about that for now, the curse will remain dormant until you achieve Juggernaut Drive." Albion explained, but then his voice turned more serious, "A Dragon's Aura responds to the feelings and can be increased with strong emotions like anger or hate, but it also because of this reason it leads many to downfall, so please remember this."

Shirou nodded as he speeded up, dividing the clouds in half as he flew through them. Half an hour later he was finally away from any civilisation.

"This should be enough," Shirou said as he landed on the ground and he dismissed his draconic armour.

Then Shirou created a barrier around him to not let the mana leak outside and to keep animals away from him.

"Indeed, this place should be safe for the ritual as I doubt anyone can sense us," The white dragon said.

"Now lay on the ground as I will start soon."

Shirou nodded and laid on the grass and waited for Albion to proceed.

"Whenever you are ready Albion," Shirou said as he took a deep breath and closed his eyes.

"Very well then…" Albion said as he started concentrating on Shirou's body. "I will start at 3...2...1…"

Shirou widened his eyes in shock as he felt an immeasurable pain in his chest, more specifically his heart, as his skin grew paler and paler. His whole body twitched in pain as he wanted to scream in agony, but no matter how many times he tried, no sound would come out.

Albion was replacing Shirou's heart with a Dragon Heart and although the process wouldn't take that long, it took a lot of concentration from Albion and a simple mistake would lead Shirou to death.

"It's done" Albion announced shortly after and the pain slowly faded. Shirou gasped as he greedily inhaled oxygen to his lungs.

"You should rest for a few days and let your body slowly adapt to your new heart and then you will feel more powerful than you ever were."

Shirou nodded weakly between his breaths and closed his eyes.

*Ba-dump* *Ba-dump*

In each heartbeat, Shirou's heart generated mana as it flowed through his entire body, making it stronger and tougher than ever before.

"This feels amazing…" Shirou said, before falling asleep in the middle of the forest.

After a few hours, Shirou woke up again and the pain was already gone, but Shirou felt that his body was still sore.

Shirou tried to stand up but with his legs trembling he almost fell to the grass. A magic circle appeared under him as Shirou teleported himself back to his room in Sakurasou and let himself fall on the bed.

'It's already evening, maybe they are back…' Shirou thought as he looked through the window, where the sun was already setting down and thew as filled with an orange colour.

*Knock* *Knock*

"Shirou are you here?" Shirou heard a woman's voice on another side of the door.

"Come in" Shirou answered and a woman with 18 years old season 4 entered his room.

"Damn, your face looks really pale!" Chihiro exclaimed in surprise and concern as she walked next to him and placed her hand on his forehead, but she didn't feel any kind of fever from him.

"It's fine, I only need to rest a little…" Shirou said with a hoarse voice.

Chihiro nodded hesitantly.

"Do you want me to grab something? Or want me to bring you to the hospital?" The Chihiro asked concernedly.

"Water and some food please, I am starving," Shirou said and Chihiro nodded and left the room.

Shirou sighed in relief and took out his phone and checked his status.

[Name: Kotomine Shirou

True Name: Amakusa Shirou Tokisada

Race: Dragonoid/Pseudo-Servant

Class: Ruler/—

Age: 16

Strength: C+

Endurance: C++

Agility: C+

Mana: A+

Luck: A+

Noble Phantasms: Left Hand - Xanadu Matrix; Right Hand - Evil Eater

Sacred Gear: Divine Dividing

Skills: Magic Resistance (A), True Name Discernment (B), Revelation (A), Baptism Rite (B+), Charisma (C), God's Resolution (C) (Sealed), Dragon-Kind Modification (EX), Dragon Reactor Core (A+)]