A single mother with two young daughters naturally couldn't afford to take in another child out of sheer kindness.
Haruto's parents sent a monthly allowance—more than enough to support three children—to Kasumi, with one condition: Haruto could stay.
Both were foster children, both were adorable little boys—naturally, the one who offered more won.
Such was the simplicity of the adult world.
Haruto and Takamine sisters had lived together as sisters for seven years—a span of time long enough for the "suffering protagonist" template to thoroughly ensnare the two sisters.
Now, only the final layer of the layer remained to be pierced.
While Haruto was engaged in what could be euphemistically called a "massage" but was in truth just an excuse to cop a feel.
Meanwhile, the Sasaki household was also quite lively.
Around the small square table, four women each occupied a side.
Recalling Haruto's earlier words, Yuki cut straight to the chase. "Reina-nee, how did Haruto suddenly become so strong?"
"Well, Haruto isn't exactly an ordinary person either..."
Reina repeated the explanation Haruto had previously fed them.
"If Haruto has incubus blood, why didn't you report it?"
After hearing this, Yuki grew even more puzzled.
The number of students in the Inner Academy wasn't small, but it certainly wasn't overflowing either. Whenever a new member joined, everyone would receive a notification.
Had she known earlier that Haruto wasn't an ordinary person, she definitely wouldn't have charged in recklessly, only to be promptly pinned to the ground and humiliated.
"While reporting it would've earned us some resources, we value Haruto more than those meager benefits."
"Haruto? Aside from his incubus bloodline, what else is special about him?"
Instead of answering, Reina said, "Yuki, try sensing the mana inside your body."
Yuki didn't understand, but her body obeyed instinctively—once the leader spoke, she acted.
"My mana has increased by about a fifth, but what does that have to do with Haruto—"
Mid-sentence, it finally clicked.
She hadn't performed any mana extraction today. Even if she had actively trained, there was no way she could've gained this much in a single day.
"Haruto actually has this kind of ability too..."
Yuki swayed between dazed disbelief, her expression flickering between delight and conflict.
"Yuki, don't overthink it. The first time yields the best results—the gains will diminish afterward."
Yukina cut off Yuki's burgeoning delusions. "About this, we still have some doubts."
"What?" Yuki looked puzzled.
"Incubi enhancing their own strength through bodily fluid exchange isn't anything special. But an incubus being able to boost the strength of their partner... that's the first I've heard of it."
"I remember you're a half-devil. Do you know anything about this?"
Reina and the other two weren't devils—they were humans who had awakened abilities.
Given their low strength, they hadn't yet had the chance to interact with other races in the Inner Academy, such as devils or fallen angels.
"Incubus are a type of devil, also known as incubi or succubi."
"There really aren't any records of incubi being able to enhance the strength of those they drain energy from. If they don't outright suck their partners dry, it's already considered restraint."
Yuki frowned, then added, "But things are different now. After so many years of development, all sorts of hybrids have emerged. I can't say for certain that none exist."
"Are there a lot of hybrids now?" Ruri asked curiously. "Haruto mentioned having incubus blood, but he didn't say he was a full incubus. Could he be a hybrid too?"
"There are indeed many hybrids, but powerful ones are rare."
As a half-devil herself, Yuki had made a point to gather intel on this subject.
"Human-devil hybrids, human-dragon hybrids, human-god hybrids, dragon-devil hybrids, devil and fallen angel hybrids... there have even been hybrids with three or four bloodlines mixed together."
The three of them—Reina and the others—were dumbfounded. "Can one person really possess three, or even four, bloodlines at the same time?"
Yuki spread her hands innocently. "Don't ask me. I'm just an ordinary half-human, half-devil hybrid."
"Is there any way to test bloodlines?"
The more they learned, the more curious they became about Haruto's lineage.
Yuki shook her head. "No idea. For most people, you can just look at their parents to know their bloodlines. Who would bother researching how to test them?"
"Haruto is a foster child. His biological parents seem to have always been overseas and never returned."
Lately, they had been spending a lot of time with Haruto. Aside from dual cultivation to boost their strength, they also talked about many things.
After all, it wasn't like they could just meet up, get straight to business, and leave immediately afterward—especially since there were temporary truces in between.
Over time, Haruto and the girls had become something like friends.
"You could ask Senior Rias for advice."
Seeing the disappointed looks on the faces of Reina and the others, Yuki suggested, "Senior Rias is the president of the Occult Research Club. She's very kind to her juniors, and I've heard she's even a high-ranking devil. She might have a solution."
"The Crimson-Haired Ruin Princess, huh…"
Yukina sighed. "Forget it. Someone like her is beyond our reach. Rather than asking that princess for help, we might as well consult Touko Sakuramachi from the next class."
"Right, I remember Touko mentioning she's a succubus. Though I'm not sure how pure her bloodline is."
Yuki's expression darkened. "Hybrids might be common, but they're not exactly everywhere. Even though we all take human forms, aesthetics and habits still differ."
That much was true. Devils alone could be subdivided into several distinct types.
Succubi or incubi were one of the more representative examples.
In the end, Reina made the decision. "Alright, once next week's tests are over, we'll report Haruto's situation to the higher-ups. By then, the benefits he provides us probably won't be as significant anymore."
"Then… will we still do it with him afterward?" Yuki hesitated.
Yukina teased, "What's wrong? Just one time, and you're already conquered?"
"That's not it!" Yuki flushed red, flustered. "That guy is definitely annoying, but compared to other men… I still think Haruto is better."
Her words were contradictory, but Reina and the others understood.
"Yuki, you don't have to worry about us seeking out other men."
Reina rested her chin on her hand, sighing. "I don't know if it's because of his incubus blood, but every time I do it with Haruto, I feel even more drawn to him."
"+1."
"+1."
Yukina and Ruri quickly chimed in—they felt the same way.
"Right now, the thought of being with another man… just doesn't interest me at all."
"Not just that. Whenever I even think about doing it, Haruto's face pops into my head."
It wasn't like men hadn't approached them during this time, but they couldn't help comparing them to Haruto.
Then, both mentally and physically, they'd start resisting—losing all interest in further conversation, let alone anything more.