Disclaimer: I own nothing, but my original characters!

#Using 'Boost' for Something Good!

When I arrived back home, I stored the unconscious Lavinia Reni, the inactive Canis Lykaon, and the remains of Penemue at my sub-dimensional base, then I left Ddraig in my room and headed for the nursery, seeking my adorable little sister. And wasn't she the most adorable angel in this world? I dared to fight Sirzechs Lucifer and Serafall Leviathan in one-in-two fight if they dared to say "their sisters are better than mine" to my face. Making enemy out of the whole devil faction be damned!

Huh? Now, that I think about it. I'd become a siscon, am I not? Curses!

But, it was impossible not being a siscon when you had the most adorable little sister in the world. I had a suspicion that Ophis's blessing affected my little sister's growth. Although she was yet to reach her first birthday, she showed intelligence above her peers and she quickly absorbed everything new in her life. But, it wasn't at the level of making me suspicious of her being a reincarnator from another reality.

My scan on her brain and soul showed she was really a newborn baby, albeit with intelligence above her peers. But, I digress.

I walked up towards the nursery through the corridor in the second floor. Hyoudou household's new living place was a three-storied mansion with the first floor containing the living room, kitchen, dining room, bathroom, and recreational room. The second floor held Mr. & Mrs. Hyoudou's room, the nursery, Gorou's study, and two bathrooms. Finally, the third floor was where Ddraig's, Ophis's, and my rooms were located.

As a side note, I had manipulated Mr. & Mrs. Hyoudou's minds with my spell so Ddraig was adopted.

Another side note, Ophis rarely used her room. If you enter her room, you will see the messed up room with scattered clothes, snack warpers, and game consoles. Yeah, the Dragon God was a lazy little thing.

I entered the nursery room and found Mrs. Hyoudou playing with my little sister, Isako Hyoudou. She was a precious little thing with brown tuft and twinkling light brown eyes. I could see that she'd grow up into a heartbreaker because of her perfect facial structure at such a young age. Apparently, Ophis's blessing affected other thing beside one's luck too.

"Nii! Nii!" Isako shrieked happily and flailed her tubby arms as she saw me entering the nursery.

"My, oh my, Ise-kun? Are you going to play with Isa-chan?" inquired Mrs. Hyoudou while putting down her baby magazine.

"Well, I wanted to check Isa-chan at first. But, I won't mind playing with her for a while." I responded Mrs. Hyoudou's question with my own. I then carried the toddler who had sked me to carry her. The moment I carefully heaved her tiny body and carried her in my arms, she laughed gleefully while clapping her hands.

"Nope! Isa-chan is a very sensible girl, unlike you." Mrs. Hyoudou's eyes became far away as she fell into a bout of nostalgia. But, she returned back to the reality quickly. "Can you keep an eye on her? I need to check out the laundry."

"Sure. Go ahead."

After that, Mrs. Hyoudou left me alone with the eleven months old toddler. I quickly checked her body and copied her aura. I did that to modify Canis Lykaon, so it would be utterly loyal to her later.

I also planned to destroy the will of entity inside Canis Lykaon, so nothing bad would happen to my adorable little sister.

For a while, I played with Isako until Mrs. Hyoudou returned back from her chore. Then finally, I headed back to my room.

When I arrived in my room, I found Ddraig walking around restlessly, her face filled with frustration.

"What's with you? Haven't you been satisfied with rampaging in Underworld earlier?" I asked the Welsh Dragon.

"I don't know why I'm still frustrated. ...No. I think I understand why I'm frustrated. The fight from before was an utter disappointment! Those fallen angels were weak, I feel disgusted to my past self for losing against them, and I needed to hold back lest I killed Albion's current host. It'd be a shame if I killed Albion's current host. With the first devil's blood in him, he is Albion's host with the biggest potential to be the strongest White Dragon Emperor in past and future. And yet, my excitement isn't sated! Raaargh!"

In her frustration, Ddraig threw her body back and crumbled on my bed, then she pulled her twin tails as if trying to rip them off.

I rubbed my chin pensively as I watched the Dragon Empress's antics. I then recalled about something and headed in her direction.

"Issei?" I ignored her question and went all four on top of her. She then froze like a dear in the highlight by my sudden audacious action. "Issei, what are yo—mph!"

I sealed her yapping mouth with my lips.

Her body stilled when I kissed her out of the blue. Her mouth tasted coppery, like blood. There was no blood in here, of course.

As she froze in confusion, I slipped my tongue into her mouth and began roaming her mouth interior. I then rubbed her left breast with my right hand and teased her stiff nipple. I then slipped my other hand into her jeans and began to play with her clit.

She quickly jolted awake from her daze and pushed my body. "What in bloody blazes are you doing?" asked Ddraig in a dangerous, low tone. Her red eyes shone with confusion and anger.

"You said you're still unsatisfied from the fight in Grigori, right? I can feel your body is excited, asking for more action, but letting you rampage around will bring trouble for us in the future. At least, my preparation isn't ready enough to take on the whole supernatural side of this world. So, I'll help you unwind your excitement." I explained calmly.

"By trying to get into my pants, you mean?" asked Ddraig incredulously.

"Well, I don't like fighting that much. So, I won't have a spar with you. Anyway, sex is a similarly exhausting activity that can give you pleasure too. Although it feels different from fighting, it has its own trill. Wait...You're supposedly an ancient heavenly dragon. You should know about this, at least." I eyed her accusingly.

Ddraig averted her eyes and sullenly responded, "Actually, I didn't know whether I had sex or not in the past. I've forgotten my earlier memory like the reason behind heavenly dragons' rivalry. What I could remember is endless training and fighting Albion. There is also my memory when I was with the past possessors of Boosted Gear, but peeking into their memories is different from experiencing it myself. So, yeah...I'm not sure about this..."

"Is that so?" I asked rhetorically. "Alright...Just believe in me about this. Although it is almost two years since my last sex, I'm confident that I can give you a good thrill that isn't less than the thrill you get from fighting."

Ddraig eyed me dubiously. For a while, we looked into each other eyes. The awkward silence enveloped us, but I kept my steady gaze on her.

Then finally, she huffed, rubbed her face with her palms, and then spread her arms wide, inviting me. "Whatever... Do your worst!" declared Ddraig while averting her eyes away.

I smiled faintly before I continued where I was before being interrupted. My tongue wrestled hers, I skillfully massaged her soft, elastic breast and teased her erect nipple, and stimulated her sensitive clitoris. Before I knew it, she tried her best to match my tongue movement. Her slender arms were circling around my neck; her left hand was gripping a fistful of my hair while her other hand was twisting the fabric of my T-shirt, almost ripping it.

I suddenly broke the kiss and looked at her flushed face intently. Her eyelids opened and closed sporadically, trying to hide her unfocused red eyes, clouded by lust. Her ravishing, pouty lips parted away slightly. Her tongue was lulling out as it sought mine. Her breath turned short and labored as she panted rapidly. Her hips were squirming, thrusting up in short, chaotic interval.

My hand could feel her intense heartbeat from her moldable breast. And finally, I felt her muscle became taut and her thighs clamped together tightly. My lips then curled up in a devious smile.

Suddenly, Ddraig's eyes snapped open widely. Her lips parted away in a silent scream. Her flexible body curved up. Her muscles tensed and spasmed.

For several seconds, she stayed like that as her climax assaulted her mind and body with the subtlety of a raging bull in a glassware shop.

Then finally, she returned from her pleasure and glared at me scornfully. "You...you...how dare you use my spell to...to..." She stuttered in rage.

"To boost your orgasm?" I finished for her.

"Yes! How dare you use my spell for something so...scandalous!"

"But, it felt good, right? That's how to use 'Boost' spell for something good!"

Ddraig's mouth flapped wordlessly. In the end, she pressed her lips thinly and looked anywhere but my eyes. "Whatever..." She responded petulantly.

I smirked smugly before I undressed myself. At my action, Ddraig eyed me from the corner of her eyes and said, "What are you doing? Why are you taking off your clothes?"

"Why? We are going to enter the main course, of course."

Ddraig frowned at my words, but she kept her silence.

After undressing myself, I undressed her next. She didn't show disagreement and let me undid her clothes. I then spread her her legs apart, giving myself the clear image of her wet pussy. She had smooth crotch for unknown reason.

I positioned my dick in front of her swelling entrance and lubricated my dick with her spilled love juice. I heard her grunt when my dick rubbed her sensitive spot and smirked at that.

Finally, I pushed my hips forward, penetrating her tight folds. I was surprised when she bled out. When I looked at her face, she was averting her eyes. I then used healing spell to lessen her pain from defloration.

I finally sheathed my whole dick inside her vice-like pussy and took a break for a moment. Then, I used the 'Boost' spell to boost up her pleasure receptors.

Ddraig still said nothing, but she peeked at me from the corner of her eyes.

"I'm going to move..." I gave her my warning before I pulled back my hips.

"Hngh!" Ddraig grunted in discomfort and pleasure from the unfamiliar yet blissful sensation. I also grunted for the tightness of her hot, pulsating pussy.

For a while, my movement was awkward because of her tightness. After her pussy loosened slightly, however, my movement became steady, following an unknown rhythm.

"Ah...Hyahn...Ah...Ahh...Hiiiii...Eek! Hyaaan!"

Slap! Slap! Slap! The obscene sound of sex and blissful moans and groans mixed and echoed in my room. It was good that I'd erected soundproof barrier before I started this.

When we were close to our climax, Ddraig's supple thighs unconsciously clamped my waist tightly and she clawed my back. At the last moment, I boosted both our pleasure receptor to get the best orgasm, and was that the most intense climax I'd ever had.

"Hyaaaaaaaaahn!" screamed Ddraig as her orgasm came. Her body was making a perfect curve. She was clamping on my body tightly, as if she was afraid I would disappear if she released her holds on me.

I spilled my seed inside her womb. Since Ddraig's body wasn't an actual body, but a body constructed from her energy, there was no danger of her getting pregnant.

After we returned from the height of ecstasy, I stared at Ddraig's flushed face. "How is it?" I asked softly.

She averted her eyes bashfully and murmured, "Fine! You're correct. Although it was different from the pleasure of triumphing a powerful opponent, it was also good." She grudgingly admitted.

But, then, she glared at me stubbornly and spoke heatedly, "That doesn't mean I agree with how you misuse my spell I'm proud of! I disliked it when you shamelessly used my Boost spell for something like that! I created that spell for fighting!"

"But, we were fighting... In bed." I gave her a witty comeback.

"You!" Ddraig gritted her teeth and pushed my body away.

At this point, her gaze turned up towards a corner of my room and she stilled.

"What's it?" I became curious because of her sudden strange reaction and followed her gaze. I then deadpanned when I saw Ophis standing in the corner, intently watching towards our position.

Was Ophis watching us having sex? How long has she been in there? I asked myself, dumbfounded. I then whispered something nonsensical under my breath, "Dragon God committed voyeur! A Voyeuristic Dragon God? Holy shit!"

My whisper was loud enough to snap Ddraig from her shock. Her body trembled as her skin flushed red in shame. She then let out a girlish shriek, "Kyaaaaaaaaah!", and kicked my stomach strongly.

Her kick sent me flying towards Ophis who blinked away from my flying path. In the end, I slammed the wall and crumbled down on the floor.

For a moment, I watched my ceiling absentmindedly before Ophis's upper bodily part entered my view.

"Issei and Ddraig, are making eggs? Is another hatchling going to be born soon? Why lesser beings like to make hatchlings?" asked Ophis innocently.

Hell no! I won't give the Dragon God a bird-n-bee talk! I quickly corrected my position and stared at Ophis seriously. "Listen well, Ophis! You can get the answer if you ask Mom and Dad."

I irresponsibly passed over the honor of educating the Dragon God about sex to Mr. & Mrs. Hyoudou.

"I, understand." Ophis nodded her head. "I, shall ask to Uncle and Aunt Hyoudou."

You two, be honored to be the only mortals who'll give the talk to Dragon God! I congratulated Mr. & Mrs. Hyoudou in my heart. I then looked at Ddraig and discovered she was rolling on the bed while covering her face. Her skin was red. I heard her muttering "I'm ashamed. I'm so ashamed! Kill me, please! I can't endure this shame anymore! " and wondered why an ancient heavenly dragon like her acting all bashful just because our sex being watched by Ophis.

"Calm down, Ddraig. It was just Ophis. Nothing to be ashamed of." I tried to calm her, but I got a scornful glare from her.

"You shameless, cretin! Shut up! A shameless fellow without an ounce of pride like you won't understand my mental pain!" barked Ddraig before she hid her body under the bedsheets.

At her angry response, I shrugged my shoulders and headed towards the bathroom.

After this, I'm going to tinker with Lavinia's mind and Canis Lykaon, then I'm going to resurrect Penemue, I mused silently as I enjoyed my quick shower.

###

Several hours since I took refuge in my sub-dimensional base, I finally completed the reprogramming of Lavinia Reni and Canis Lykaon. I'd stored Canis Lykaon in its inactive mode, a shadowy black egg, in my safe storage. I would release it later at the birthday of Isako a month. I'd resurrected Penemue too.

As a side note, I had pumped more mana than necessary when I resurrected the female cadre, giving her last pair of wings. Penemue was now a Seraph level fallen angel.

I watched both naked Lavinia and Penemue on top of their operation tables. Thankfully, I'd had sex with Ddraig before I did this. If not, my focus would be split between my work and keeping my sex drive at bay.

Both Lavinia and Penemue had seductive bodies and perfect curves that would make any healthy and straight male lust over them. In fact, I had contemplated the idea of using their body for quickies when they were asleep. But, I discarded that idea because sex with wide-awake person was much better. For their appearances, Lavinia had long flowing blond hair and curvaceous figure with 100/59/88 three sizes and standing at 170cm, meanwhile, Penemue, had intense purple eyes and matched flowing hair. She was a bit taller one and had equally buxom figure.

I nodded my head before waking them up using magic. Slowly, their eyes opened. They blinked in confusion and sat up on their spots before checking the plain white room until their gazes stopped at me. I could see their confusion. They were most likely feeling confused as to why they felt inborn loyalty and devotion when their gazes locked at me.

I smiled faintly to them and said, "Well, hello my dears. Welcome to the living world. I'm your master and creator. Call me master when we are in private, but you shall call me Issei when we are in the presence of others."

I turned my gaze towards Lavinia first. "Your name is Lavinia Reni, you're based on your predecessor with the same name. You're my slave. I want you to repay the life I bestow upon you with your unquestionable devotion and loyalty."

Of course, what I told her was mostly bullshit. Making them think they were a copy of their former selves was a good move in the long run. I then turned my gaze towards Penemue.

"And you, my dear, you're Penemue, after your predecessor with the same name. Like Lavinia, I want your unquestionable devotion and loyalty to repay the life I bestowed upon you."

I paused and alternated my gaze between the two. "Am I understood?"

Lavinia and Penemue nodded their head before climbing down their operation tables. They kneeled humbly in front of me. They then raised their face, showing their eyes filled with reverence.

""My body, soul, and power are only for you and you alone, my master!"" They swore their loyalties at once.