Over the next two days, Mei spent most of her time testing the enhancements from the Signet of Infinity. Mobius was, after all, a dangerous individual, and Mei didn't dare rush into challenging the 16th floor with the new Signet without understanding it better.
Unexpectedly, however, she didn't feel any negative effects or constraints. On the contrary, with the Signet's help, she successfully completed her trials, arriving at the entrance to the final floor.
"Did Mobius really not tamper with the Signet?" Her doubts didn't lessen; instead, they grew stronger. Given Mobius's undisguised malice, Mei couldn't believe she wouldn't set some kind of trap.
But stalling was pointless; she couldn't stop moving forward simply out of fear. After confirming once more that the Signet seemed safe, she returned to the area she had initially chosen, but this time, she stood before the door to the sixteenth floor.
"Hope this goes smoothly." Exhaling slowly, Mei stepped through with determined eyes.
However, behind the portal wasn't a powerful enemy, but a familiar laboratory—Mobius's lab.
Not long ago, she had received treatment from Mobius in this very lab; she couldn't possibly forget it. But back then, her impression was that, aside from being a bit sterile, it wasn't drastically different from a normal laboratory. Yet, what appeared before her now was an area as frigid as an ice cellar. If the lab door hadn't looked exactly as she remembered, she might have thought she'd stumbled into a morgue.
Suspiciously, she walked to the laboratory door. Just as she prepared to push it open, she noticed the sign above wasn't a familiar department designation, but a twisted, serpentine symbol. At first glance, the serpent's mouth gaped open, seemingly poised to swallow her whole.
"What is this?" Her heart sank, and she hesitated. The feeling this place gave her was deeply unsettling; it felt less like entering a lab and more like stepping into a hibernating snake's den.
Despite the strangeness, she braced herself and went inside.
The laboratory was pitch black, illuminated only by dark green emergency lights that glowed like snake scales. She wasn't attacked as expected; it was eerily calm. Inside, aside from scientific equipment, there was only a single door leading elsewhere.
Strangely, this door looked almost identical to the one Mei had entered through, even down to the way it swung open. Suppressing the odd feeling rising within her, she pushed the door open again—only to find herself in the exact same room.
"Infinity..."
It was like being caught in a loop, no matter which door she opened, she arrived in the identical space, like traversing an infinitely extending serpent, never reaching an end.
"Cheap tricks," Mei scoffed. Arcs of lightning burst from her body, instantly activating the surrounding power systems.
The dim space flooded with light, revealing she wasn't in a series of labs at all, but merely a long corridor. Each door she had opened simply led back into the same corridor.
"Following this passage should lead out." The reveal saved considerable time. Although the corridor still seemed to stretch infinitely, her electromagnetic senses told her the end was just ahead.
Just as expected, another door appeared at the corridor's end. This time, however, it stood wide open. When she passed through it, she finally arrived in a spacious area. Turning back, she watched as the doorway she'd just used began to collapse, eventually disappearing completely.
"Tsk, trying to trap me here?" A cold smirk touched her lips. Mei looked directly into the darkness ahead. "Come out, Mobius. Your little games should be over."
The air was silent, until a faint, slithering sound began. Then, a figure slowly emerged from the gloom.
"Hello there, little lab rat. I've been waiting for you for quite some time."
"It really is you!" Mobius's appearance actually made Mei sigh in relief. Although Mobius looked dangerous, at least she was a known quantity.
"Oh my, Big Sister, you're the one who barged into my domain, yet you're blaming me?" Mobius put on an innocent expression, looking pitifully at Mei, but the smirk playing on her lips completely betrayed her malicious amusement.
"Heh, you gave me the Signet precisely because you wanted me to come here, didn't you? Stop playing these cheap tricks. If you need to test me, I'm ready whenever you are."
"Test? No, no, no, I don't need to test you at all." Mobius narrowed her eyes, her serpentine pupils brimming with almost palpable malice. Despite her childlike appearance, she gave off the distinct impression of a predator eyeing trapped prey.
"I want to devour you." She grinned, revealing a predatory smile.
The moment her words fell, a wet, slick slithering sound seemed to emanate from the darkness. It grew closer, seeming to crawl up Mei's spine, licking at the shell of her ear. The grotesque sound made even Mei shudder involuntarily. She subconsciously reached behind her back, but felt nothing besides her own cold sweat—there was no snake.
"Enough, Mobius! After becoming a MANTIS, surely you don't actually think you're a snake, do you? I am not your lab rat, and I am certainly not your food. Keep these malicious jokes to yourself."
"Hehe, you think I'm joking? Raiden Mei, I meant it literally. I am going to devour you—your consciousness, your very self."
Mobius sounded serious, but Mei found it ridiculous. Besides, even the most patient person has their limits, and after Mobius's repeated taunts, anger flared within her.
She sneered, mocking, "Devour me? Have you been in the Elysian Realm so long you've forgotten you're just a memory simulation? Besides, my real body is in the physical world. Don't tell me you plan to swallow my real self too?"
"Bingo. Congratulations, you've guessed the correct answer."
"What?" The expression on Mobius's face made Mei's heart clench. She didn't look like she was joking at all. But this... how could it be possible?
Like a predator tasting the air before the hunt, Mobius extended her tongue and licked her lips, seemingly preparing for a meal. "Have you forgotten what I told you? A lab rat's value is in helping me explore the unknown. But sometimes, to satisfy one's own thirst for knowledge, one must make... radical choices. The information you've provided is simply too interesting; it's made me incredibly curious about the world outside now. So..."
"I want to use your body to go see it for myself!"
"Use my body? But aren't I also in the Elysian Realm... Wait, you mean my body in the real world?" Realization dawned late on Mei, startling her. Her eyes filled with disbelief.
"Exactly, exactly! You should know, right? As long as your consciousness dies here in the Elysian Realm, your real body will fall comatose. At that point, World Serpent will undoubtedly initiate a rescue operation. And I will disguise myself as you, infiltrating and taking over your physical body." Like a classic villain announcing their evil scheme before the final battle, Mobius's voice rose with excitement, as if her plan had already succeeded.
But Mei hadn't lost her composure. She calmly pointed out the flaws in Mobius's plan. "Even if I die here, World Serpent would never allow data from the Elysian Realm to just flow out. Taking my place won't be that easy. If you really had this capability, you would have already done it with previous trial-takers."
"Indeed," Mobius surprisingly nodded in agreement, but quickly added, "However, do you remember that 'accident' when you first entered the Elysian Realm? Although Elysia and I couldn't pinpoint the cause of the malfunction, we did detect a mysterious signal. This signal bypassed the Elysian Realm's defense mechanisms and wasn't even detected by World Serpent. As long as I use that, I can completely avoid World Serpent's scans."
"!" Mei, knowing the signal's origin, was abruptly startled. She knew The Obsidian Concord could indeed bypass the Elysian Realm's defenses, which meant Mobius's plan... could actually work.
"Teehee, judging by your expression, you've figured it out, haven't you?" Mobius let out a shrill laugh, and even the air seemed to grow exceptionally cold.
Although panic fluttered within her, Mei skillfully hid her fear. She retorted mockingly, "But all of this hinges on you actually being able to kill me. I admit the strength of a MANTIS is formidable, but thinking you can kill me based on that alone is rather naive."
As she spoke, her blade became a streak of light, slashing towards Mobius. But just as it was about to connect, a massive black shadow suddenly darted out from the darkness, blocking the attack.
"Mmm, it seems you still don't know the true source of a MANTIS's strength. No worries, you'll see it soon enough."
As Mobius finished speaking, the black shadow struck again. Mei's expression tightened as she quickly raised her blade to parry. But the shadow's power was immense; she was instantly sent flying. Only then did she realize the black shadow was actually a massive snake tail covered in black scales.
By the faint light of the residual electrical arcs, she finally saw the snake tail's origin—it was connected to Mobius's body.
"Mobius?!"
Within the shapeless darkness, shadows writhed continuously until, finally, the form took shape completely before her eyes.
The Mobius with the appearance of a young girl had vanished. In her place stood a monstrous body of immense size. It held a scepter, and from its base upwards, it was covered in black snake scales. Only by looking up at the upper body, towering over thirty meters high, could Mei barely make out Mobius's comparatively small torso integrated within.
"You... why do you look like this?"
At this moment, Mobius showed none of her earlier playful malice. In this state—her Artificial Cascade—she could only barely maintain her sanity. She lowered her colossal head, looking down coldly at Mei. "Witness the Artificial Cascade of a MANTIS."
Under that immense, scrutinizing gaze, Mei truly felt like a tiny, helpless lab rat that had stumbled unknowingly into a python's trap.
"Struggle. Flee. But unfortunately, as the serpent's prey, you cannot escape."
The madness in her tone grew more unrestrained. The entire laboratory area transformed completely into the serpent's hunting ground. Raiden Mei's expression was one of terror, her deep violet eyes reflecting the image of a world-devouring Serpent of Infinity.
「This is the moment of apotheosis!」