Academy's Traitor (10): The Master-Servant Contract
A spell that binds the target's mind through mana as the medium. Once established, the designated servant develops unwavering loyalty and intimacy toward their master.
These emotions, artificially instilled through magic, remain unchangeable as long as the contract endures.
Due to its simple yet potent effects—indistinguishable from numerous black magic brainwashing spells in efficacy—the use of Master-Servant Contracts on humans has been strictly forbidden by law for ages.
Moreover, it persists almost semi-permanently unless broken by external intervention, compelling the target to choose obedience of their own volition, allowing for insidious exploitation in certain cases.
However, it has a clear drawback: the contract cannot form unless the target willingly accepts it. Thus, prior coercion or consent via other means is required for the magic to take hold.
"I... I'll do it...?"
Finally persuaded, Erin stood there hesitantly, staff in hand, glancing my way. She still harbored some lingering reluctance. It made sense—after all, this was essentially brainwashing herself.
"Yeah. Do it."
I gave a curt reply, fixing her with a piercing stare that silently demanded, You wouldn't back out now, would you?
"Summoning Magic: Master-Servant Contract...!"
"By the threads of mana, we bind soul to soul."
"Master's will becomes servant's truth, eternal and unbroken."
⟨ Master-Servant Contract ⟩
Erin aimed her staff at herself and activated the spell. A brilliant azure glow erupted from below her navel, forming a white orb that floated gently in the air. It was a fragment of her soul—pure and transparent. Though tainted by suggestions, her core nature still clung to its original nobility.
I reached out toward the orb. The moment my fingertips touched it, it shuddered violently, gradually staining with murky hues. Once fully blackened, sinister runes etched across its surface. The corrupted orb was drawn back into Erin, imprinting a large, unmistakable mark of the contract just below her navel.
I pulled out my phone to check her affection level.
Not just MAX, but infinity. It must reflect that her affection would never drop as long as the contract held.
I tapped the affection stat to open the window detailing her thoughts about Id. But contrary to expectations, it was blank—not empty, but like a editable field waiting for input. On a whim, I typed in [Id's Slave].
"Contract... complete..."
Erin slowly opened her eyes and murmured. She looked at me and smiled softly—a expression devoid of her usual arrogance, filled only with pure obedience. It was disgustingly cute.
"Lick."
I extended my shoe.
"Yes♥ Master♥"
Politely kneeling, Erin crawled to my feet, lowered her head, stuck out her tongue, and began licking my shoe. The moment the contract took hold, I'd broken my promise not to force her—but she showed no sign of protest.
Not surprising, really. Ea, with her mere +200 affinity, had eagerly sold off her cherished junior just to please me. What wouldn't an infinite-affinity Erin do?
"Forget about being lovers. From now on, you'll live as my slave and obey my commands. No objections, right?"
Pausing mid-lick, Erin looked up with a sycophantic, groveling grin.
"Yes♥ Command me however you like, Master♥ Erin is Id's slave, after all...♥"
Another one in the bag.
True to my word, I had Erin summon Ea.
"...Good. I'm glad you changed your mind."
Seated on the sofa, Ea sighed in relief upon hearing Erin say she wouldn't report me. She must have been worried deep down. Since I'd strong-armed her into cooperating without details, she had no idea about the full picture—just that she'd brewed the herbs I gave her and served them to Erin as tea.
"...But Id."
Ea turned to me and whispered just loud enough for me to hear.
"Erin's watching... aren't you groping too much? Nngh...♥"
Her face flushed crimson as she stifled a hot gasp, lips pressed tight to contain the moan—but it leaked out anyway. I'd glued myself to her side, relentlessly pinching and twisting her nipple.
"Doesn't matter, sis. What do you think, Erin-senpai? How do we look?"
I asked outright. Erin beamed.
"You two seem awfully close."
"Doesn't it look weird?"
"Not at all. Siblings getting along is a positive thing."
Erin recited the lines I'd pre-programmed into her with mechanical precision. Ea, clueless about the truth, looked puzzled by the bizarre conversation flow.
"Erin...?"
"Never mind that, sis. Since she's here, let's show her more of our sibling bond."
I slipped my hand between Ea's legs and thrust fingers into her pussy. Per my standing orders, she wore no panties or bra—and she was already soaked—so four fingers slid in effortlessly.
"W-wait, you—Id! I said no...!"
Maybe because her most treasured junior, who always looked up to her adoringly, was present—Ea freaked out and shoved my hand away with all her might.
"Tch."
I glared at her, feigning anger. She deflated instantly, eyes darting nervously to gauge my mood.
"Sis, you keep ruining the mood. I said it's fine, didn't I? Don't piss me off. You gonna keep defying me like that?"
"S-sorry..."
"Then strip. All of it."
"S-strip...? But inside, it's..."
Lewd graffiti, tattoos, even piercings adorned her body. The model of virtue who preached chastity and proper conduct was hiding such depravity under her uniform. And now, her cherished junior would see the student council president—a role model for all—exposed in filthy glory.
So unlike her usual self, she hesitated fiercely.
"Can't we do it at home...?"
"Strip."
I put force into my voice. Ea wavered, then stood and began peeling off her clothes one by one.
As she undressed, she stole glances at Erin, hoping she'd intervene. The old Erin might have—but not this one. Even her respected senior ranked far below my commands. If anything, she smiled contentedly at Ea's obedient compliance, as if reassured that her senior had fallen just as far.
"S-stripped..."
Ea stood bashfully, arms covering her breasts and crotch. It didn't hide the obscene scrawls plastered across her body or the piercings embedded everywhere.
"What do you think of sis's look? Be honest."
Erin replied,
"...Disappointing. I thought Ea-senpai was a model student and chaste woman like no other. To hide such a slutty sight under her uniform..."
Her words dripped with venomous scorn. Ea's face crumpled as if on the verge of tears, head bowed low. She seemed heartbroken—but that was only half the truth. Ea's kink was masochism. The more she was tormented, the more she felt it. She was surely reveling inside. Her body trembled with shivers, love juices dribbling freely between her thighs as proof.
"Don't worry, sis. Erin-senpai already knew everything."
I circled behind her, kneading her ass as I spoke.
"Knew...?"
"Show her, Erin."
"Yes♥"
At my order, Erin eagerly shed her uniform, baring herself completely.
"Erin...?"
Ea blinked in confusion at her junior's sudden action. Then her gaze locked onto Erin's lower abdomen.
"That tattoo... no way..."
"It's the Master-Servant Contract mark. I just formed it with her."
"Formed it...? You used a Master-Servant Contract on a person? Id, that's illegal."
"So what? She wanted it. Besides, I didn't cast it—I'm clueless about contract magic. You know that, sis. The expert in that field is Erin-senpai."
"No..."
Ea murmured in disbelief. Then Erin drove the nail home.
"Yeah. Don't misunderstand, Ea-senpai. I cast the Master-Servant Contract on myself and accepted it."
"Why would you do that?! You know better than anyone what kind of magic it is...!"
"Because... he said he wouldn't fuck me anymore if I didn't...♥ I want to keep getting tons of love from Id...♥"
Erin spread her pussy lips with her fingers, letting the cum I'd dumped inside earlier ooze out as she spoke.
"That's too much... too far, Id... You've crossed the line..."
Ea muttered in shock. I wrapped an arm around her shoulders while pressing down hard on the plug in her ass with my other hand.
"Saying that now? You handed Erin-senpai to me yourself, sis."
"That was because... I trusted you..."
"Liar. It was to win my love. You'd do anything to please me—that's your true nature."
One of Ea's sexual preferences: immoral acts. A new kink I'd cultivated during her training. She got intensely aroused by unethical, decadent behavior—a twisted desire born from her high pride, sense of justice, and contrasting lewd depravity.
"I... it's not like that..."
"Then leave me and go back to fapping alone without me?"
"That's..."
Ea couldn't respond. I ground my bulging crotch against her ass, whispering temptations.
"Think about it properly, sis. How about you form a Master-Servant Contract too?"
"A Master-Servant Contract...?"
"No need to feel guilty. Our relationship stays the same—maybe even closer. You know all about magic, sis; it's not the type that breaks the mind. Just a bridge drawing us nearer."
Gulp. Ea swallowed hard. Her eyes flicked to Erin. They met, and Erin smiled sweetly.
"Senpai♥ You're not planning to ditch me alone, right?"
Ea's pupils quivered violently. Pre-instructing Erin to play along had been spot-on.
"If we form the Master-Servant Contract... I... can get even closer to you, little brother...?"
She gazed up at me from inches away—not so much a question as a plea. This was how far the once-unyielding genius swordswoman had fallen.
"I told you, sis—you're always number one."
I licked her nape. Her lips slackened into a faintly sinister smile.
"Then... I'll do it... with you, little brother... Master-Servant Contract♥"
The tireless, unyielding genius magic swordsman. The elegant, noble daughter of the Leonin house, overflowing with integrity. Swordmaster among swordsmen, mage among mages, lady among ladies.
Such a woman existed no longer. Ea had fallen.