After he took Asia with, Miyuki is slowly corrupting Asia's way of thoughts and her emotions, he didn't use any power to alter minds.
He's using his skill being a psychology student, understanding emotion is one is a necessary skill to have an understanding of the nature, causes, and control/regulation of emotion, or as the way in which the child identifies, predicts, and explains emotion in him/herself and others.
Miyuki could sense, fear, sadness, and anxiety. Miyuki wondered why Asia didn't have any sign of being anger.
"Asia, I have a question, what if GOD is already dead and thr heaven covers it up"
Asia was shocked by his question "Hyoudou-san, GOD is powerful he can't die"
Miyuki grins "That's what you're wrong the war between three factions where God, the devil kings, and Azazel have an intense fight Azazel withdrawn to the fight and went back to his base Grigori. Later GOD withdraw in the war too, but succumb to the injuries he receives and died "
" Currently Michael is the whose managing the heaven, he's acting as god so no outsiders would know, if they know they wage a war, another bloodshed and innocent will practically would get involved and DIE"
Miyuki says half truth and pure bullshit, he actually don't know how god died in this world.
Asia: "It can't be... You're lying"
Miyuki shook his head, and patted her head "You heard what I said and then called me a liar. Now, you're refusing to believe what I've said. Your mind may not want to accept this revelations but inside you there's a voice saying... Accept it, it's the truth."
Asia gasped she covered her mouth, her eyes widened tears forming on her beautiful green eyes.
Miyuki: " Soon you'll know, time will help. I feel sorry for your confusion but this world is never been about truth or lies. In this world, there's only one thing that is worth knowing. Hard facts! Despite this universal truth people misguidedly choose to only accept that appealing to their way of thinking. They're so limited. They can only accept the truths that are comfortable for them. "
Asia lowered her head, she's overwhelmed by the statement Miyuki shared to her.
Miyuki: " So, this simply about wanting to hung your personal beliefs. Realizing things may not have been as we accept them to be unsettles us, it's overwhelming isn't it Asia"
Asia didn't utter any words since before
'Did I break her mind? I will leave her be I'm a protagonist that able cheer up a girl'
Miyuki silently left the room, Asia watch him leave her eyew are filled sorrow.
'No wonder my prayers did not came true'
Asia thought as she lie down on the bed, she closed her eyes and went to sleep, as she can't accept the harsh truth that the church hide to it's people.
Addition to that is that she was sold to someone, and got lured by the excommunicated people from church to become a sacrifice.
Asia feel asleep with tears flowed down from her close eyes.
...
Outside of the house, Miyuki is casting a spell, it's a wide range spell that cover the whole woods with detection magic, Miyuki then casted a spell an invisible barrier covering 5,000 square meters of land.
'I'm not super dumb reincarnated person to the point of forgetting to place barriers even knowing that he hold a power that can threaten supernatural beings, ultimately killing their loves ones and go revenge killing innocent lives'
Miyuki still remember about that fic's mc's mistake.
'I should place a barrier to my house too, just for counter measure'
'Oh nearly forgot place protection spell around the barrier, in case someone entered in my territory without being detected'
Miyuki began placing a crimson runes around the barrier. He learned it from Wanda Maximoff after she used a protection spell via magic runes to neutralized Harkness's magic, and revitalized her own magic, even after having been drained of it.
'This is all good, as for the next phase time to reach same level rivaling ultimate class devils'
Miyuki could detect many demonic energies around, those energy are from stray devils that always loves to go in this area as the woods were quite big dark.
Miyuki went out from the barrier towards the nearby stray it's 30 meters away from his place.
Not for long Miyuki found the stray she's a skinny woman.
'Low class strsy devil, no complaints it's still an energy to be absorbed'
Miyuki appears in front of her saying.
"Pick a booo!!"
The female felt like she will have a heart attack and after knowing that she got scared by a puny human, she got furious. When she's about attacks the puny human, he grabbed her neck and lifted her up.
"HAHAHA!! You're too slow devil"
After laughing, Miyuki began absorbing her Demonic energy, the female stray rapidly became weak she can't move her body as if her energy was drained.
After Miyuki completely siphoned demonic energy from the female stray, he dropped the stray.
"Be something different on your life"
Miyiku says with cold viece, as crushed her skull stepping on her head.
'It gives me insignificant amount of energy, I need more'
Miyuki went to hunt more living batteries.
...
"BROTHER!! ASIA!"
Issei shouted as he wake up, his injuries were healed by Akeno. Issei look around the room is familiar, recognizing that he's at the Research Occult Club. Issei's expression turned grim, Akeno went on his side and comforted him.
"Where's my brother? Why he did it? I want explanation!"
Rias with stern expression, stare at him and sighed "Your brother is a stray devil hunter, I think you already heard it from him. He have a message to you Ise grow strong, stronger than anyone if you want to defeat me"
Rias saysshe altered some words Miyuki said as per Miyuki whispered to her to do it, after Rias failed to grab his hands. The reason complied it's also a good thing for her to break away shackles of marriage.
'I'm sorry Ise but this the only way to boost your determination to grow stronger supernatural world isn't a good place for a good guy like you'
Issei understood and nodded, clenching his fist, Issei vowed to get stronger, as Miyuki's voice is still lingering in his mind 'From this day on, I will train seriously and reach on his level NO! I will surpass him and make him acknowledge me!'
Seeing Issei's determination everyone in the room also happy to Issei found his reason to get strong.
After the brief moment of silence, Issei spoke.
"Buchou, What happened to Asia? You know the blonde nun"
Rias shook her head "I'm sorry Ise but she isn't here, after all teleportation circle only works on me and peerage"
Issei's expression turned gloomy 'I'm indeed too weak I can't save Asia'
"Buchou what stray exorcist? I heard that from him"
Rias began to explain what is stray exorcist, the difference of exorcist working to church and stray exorcist thst found a pleasure killing devil and anyone contracted to them.
Issei: "How can they wield power of light?"
Rias: "They can able to wield power of light due to the tool they use like from the ex-priest you encounter. The church exorcist received from GOD after doing a ritual. As for stray exorcist they allied themselves to the fallen angels and receives the power of light"
Issei seems to understand one thing and that is fallen angel and strays are evil.
Issei: "Buchou, I need to save that girl, Asia from their hands"
Rias: "It's impossible. How will you fight them? You're a devil, she's a servant of fallen angel. It's the two kinds that cannot coexist. Saving her means making the fallen angels your enemies. If that happened, we would alse have to fight.
Issei couldn't retort, he's indeed going to drag them due to his selfishness.
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[I kinda rush the last part, feel free to comment your view my readers.]