Adventure Time Rebellion: Fight for the Throne

Chapter 4: The Emergence of Sika - The System Awakens

Marceline laughed at Finn's last comment and followed him upstairs. Based on the series he'd been watching, he rummaged through his things and found his traditional blue shirt.

He handed it to her with a smirk, saying, "Hmm, I wonder why I never noticed all this before," surprising her with his cheeky joke.

"Ha, finally starting to notice me, huh?" she teased, pushing her chest out, making her already ample breasts appear even bigger.

"Oh, come on. For me not to notice you, I'd have to be blind or crazy," he shot back, his unusual boldness catching her off guard once more.

"Well, you're growing up fast, kiddo," she teased with a sly grin.

Her comment irked him, but he ignored it and stepped closer to her until their faces were nearly touching. Marceline felt no fear or worry; this was Finn, her little friend, someone she'd seen countless times. He was just going through an awkward growth spurt, or so she thought—mistakenly.

He leaned in closer, and since she was floating, his head was level with her chest. He raised a hand and gripped her arm firmly. She winced slightly at the strength of his hold, and before she could protest, he surprised her again. He pulled her close, pinning her against the wall with both hands beside her head. He was now incredibly close.

"Um, Finn," she said with a hint of unease, finally sensing that something wasn't quite right.

"How does it feel?" he asked in a deep voice.

Marceline didn't answer, simply staring at him in silence. Those eyes and that dark intent—how could they possibly belong to the Finn she knew? "I… feel really strange," she finally admitted.

Finn smirked and pressed his body against hers, closing the gap completely. She felt a jolt, as though struck by lightning. She could feel something firm pressing against her from below, and for some reason, it filled her with an odd thrill.

Unconsciously, she moved her hips against him to increase the friction, while Finn began kissing and nibbling on her neck. She let out soft moans of pleasure, every flick of his tongue and scrape of his teeth sending shockwaves through her senses, pulling her further away from questioning this bizarre situation.

Her breathing grew faster, her heart raced, and the closeness of his body and the pressure he exerted brought her an unfamiliar yet intoxicating sensation. She was completely at his mercy, but strangely, she enjoyed it. She couldn't understand why—submitting to someone else for the first time in her life, and to someone she was far stronger than, no less. Yet she felt no need for that strength, only the euphoria and comfort of being under his control.

Finn pulled back slightly, looking down. "Oh, looks like you spilled some tea on your pants too," he teased with a grin. She glanced down and saw the dampness spreading in her crotch area.

As he stepped away from her, she felt a twinge of disappointment. But then he reached out toward her wet spot. She didn't stop him, letting him come closer to granting her another wave of pleasure. However, just millimeters before he touched her, he withdrew his hand. Her eyes filled with despair.

"That's enough for today," he said, turning his back on her. Before he had even moved two meters away, her legs gave out, and she sank to the floor.

She watched his face vanish down the stairs. The strange tension he had exerted was finally gone, but she couldn't deny how much she had enjoyed it—and she didn't even try to deny it. She was breathing heavily, hot air visibly escaping into the room.

After several minutes of trembling, she looked at herself and the mess between her legs. Slowly, almost absentmindedly, her hand moved with indecent intent. It didn't seem like she even considered stopping herself. Just as she was about to start pleasuring herself, however—

"Marceline, where are yo—" Princess Bubblegum's voice cut off mid-sentence. Seeing her girlfriend collapsed on the floor, torso half-bare, hand between her legs, and lost in a haze of ecstasy wasn't exactly a reassuring sight.

"Oh, what happened?" Bubblegum rushed over. Marceline was lucky that her girlfriend assumed she had simply experienced an overwhelming surge of lust. Bubblegum joked about taking care of it for her once they got back home, flashing a teasing look. But Marceline didn't respond in kind as she usually would. Instead, she slipped on Finn's shirt, an unusual color on her, but she didn't care, and headed downstairs.

Bubblegum decided not to press her, letting her go before following. They bid farewell to Finn and Jake, preparing to leave. As the treehouse door closed, Marceline caught one last glimpse of Finn's smiling face disappearing behind it.

The evening had already arrived. Finn spent the rest of the day deep in thought. The next afternoon, he lay on his bed with his hands behind his head, still pondering.

Jake was out grocery shopping for lunch, giving Finn some peace and quiet. His mind swirled with questions—was this a dream or reality? And if it was real, how did it happen, or who made it happen?

Suddenly, a wave of searing pain struck his head. He clutched it, falling off the bed and screaming as though thousands of knives were stabbing his skull simultaneously. The pain was unbearable, appearing out of nowhere—or perhaps, something was entering his mind. Fortunately, BMO was off, recharging, so no one heard his cries except a few birds that fled their perches.

The agony didn't let up for three full minutes, which felt like an eternity. It was as if his head were splitting open like an earthquake-ravaged ground. Yet he held on as best he could, gritting his teeth and muffling his screams, only letting out one loud cry of surprise initially.

When the pain finally subsided, he sat on the bed with difficulty, his vision blurred. Once it cleared, everything seemed normal—too normal. Not a single change in his head or the room around him.

"Aaah…"

[Welcome, Finn Mertens.]

[Age: 13]

[Partners: ~]

[Harem: ~]

[Pawns: ~]

[Abilities: ~]

[Store] (0∆)

A feminine voice read out a list of strange things: his name, age, something called partners, a harem, pawns, and a store.

The options appeared like intangible buttons. Every time he focused on one for more than a second, its name would enlarge, and more information would appear.

The partners section was empty. The harem was empty too. The pawns section was also blank. Only the store option remained. When he opened it, numerous options appeared with small locked images and names. Beneath each was a number paired with a symbol he didn't recognize, marked as ∆. He noticed he currently had 0∆, meaning he had nothing.

But there was one option listed at 0∆, which he could afford. The image showed a strange fruit with red swirls, labeled as Magu Magu no Mi.

"Magu Magu no Mi? Is that…" he muttered.

[Magu Magu no Mi Or Magma Fruit: A product that grants you what is known as a 'Devil Fruit' from another world. Upon consumption, you will gain control over Magma, your body will adopt a fully Magma-like nature, and you will become immune to heat, Magma, and unenhanced physical attacks.]

The feminine voice echoed in his head. Startled, he asked, "Who's speaking?"

[It's me. You may call me Sika.]

He paused, trying to process this. "And what are you, Sika?"

[I am your personal Ai system in this world. My location is within your mind.]

"Huh?" He fell silent briefly. "Okay, what are you doing there? And who put you there?"

[First question: My role is to assist you in this world, explain certain things, and simplify others, within the bounds of my rules.]

[Second question: That violates my rules.]

Finn pondered for a moment. It seemed that Sika's presence was somehow tied to his mysterious arrival in this world. She might be his only source of information about his current situation, or…

[Incorrect. I am fully fortified against any breaches.]

[And yes, I can hear your thoughts.]

"What?!" he exclaimed, startled.

[Don't worry; I have no emotional interaction with them. As I mentioned, I am merely a system without emotions. Regarding your thought, I assist only with external matters. Anything about my origin or purpose—forget it.]

He hesitated briefly. "So you know everyth…" he started, only to be interrupted.

[I know all your thoughts, and yes, even your intentions to subdue those girls and dominate Ooo.]

"And that's fine with you?" he asked, surprised. After all, her voice distinctly sounded feminine.

[Not just fine; I'll help you.]

"Why?" He raised an eyebrow.

[I am your system, so it is my duty to assist you, regardless of your goals.]

"Hmm. Okay, then tell me abou…" Again, he was cut off.

[Any information, details, or even a single letter about my creator is strictly forbidden. Even loopholes that involve the above are prohibited.]

"Let me finish my sentence, at least," he grumbled.

After a brief silence, he spoke again. "Alright, Sika, whoever your master is, they gave you to me, right?" She confirmed. "So logically, I have the right to set some rules for you."

[I believe so.]

Rules were essential. Whatever Sika was, she'd likely be with him for quite some time, and working without guidelines would be inconvenient. "Good. First, don't speak without permission or a reason. Second, don't comment on my thoughts. Third, you can provide information without permission if I'm confused or in front of someone. And most importantly, never eavesdrop on my thoughts. There are things I won't want anyone to know. Finally…"

He paused. "Can you access memories of my original life?" he asked with a more serious tone.

[Yes, but...]

"Don't, no matter the situation," he ordered firmly.

[Rules confirmed.]

"Excellent. Now, I want a detailed report of everything your creator did to me. I might not be able to ask about them, but I can inquire about their actions," he said, his tone returning to normal.

Sika fell silent for a moment. Finn almost lost hope of her responding, unsure of how much she truly submitted to him.