The tunnel was spacious, with multiple torches and lamps attached to the walls, not giving any chance for darkness to conceal the ground. Beside Iris, other Monster Girls occasionally went up and down, passing Iris, minding their own business.

Their tattered appearance made them look pathetic, but the gleams in their eyes and the excitement in their rapid breathing announced to the world that they had gained substantially from their deadly adventure. With every such occurrence, the descending Monster Girls grew impatient and increased their pace, but not Iris.

Despite the agitation, she maintained her pace, yet her chest tensed as she descended deeper. Though she couldn't pinpoint its origin, an omen plagued her mind. She glanced around and found nothing. The neighbouring Monster Girls, even the Transformation Phase ones, expressed no such concern, still eager to participate in the Legacy Ground. Their relaxed voices pricked at Iris, almost driving her crazy.

Either Iris lost her mind, or there was a force so great and esoteric not even the powerful Monster Girls could detect it. If not for her otherworldly origin and the Shadow Heart Core inside her, Iris would similarly feel nothing.

Still, it was comforting knowing that something was watching over her. At least this force wasn't overwhelmingly mighty like Gulia and Lilith, whose presence she couldn't even fathom, despite being so near to them. They might be watching over her, but they were her ally. Her continuous existence benefited them; they wouldn't harm her, at least until she served her purpose.

It was an issue of power. If Iris were too weak, she would get discarded, her life abandoned, her family taken away.

"Ahead is a crisis, but behind is death," Iris murmured. "Will I ever get to rest?"

"You can rest if you come with us," a hushed voice rang behind Iris.

A group of three Monster Girls approached Iris. The leader of the group, a black-scaled Snake Girl, slithered to Iris and smiled at her. The other two, a Lily Girl and a Beetle Girl, closely followed behind. They all were at the Metamorphosis Phase, though confidence was overflowing from their manner.

"We three want to enter the Legacy Ground, and the more member, the less risk," the Snake Girl said. "You're a strong Slime Girl, Sister. We need a Monster Girl who can control Water Element like you."

"You all should go without me," Iris said. "I won't be able to integrate into your team."

"The more people, the easier the test, right?" The Beetle Girl clasped her insectoid hand and lightly beat against her modest chest. "I can protect you. You only need to provide support. It is a safe position."

"The Legacy Ground wouldn't have a loophole like that. The difficulty will scale with the number of participants. It would be more beneficial for us both to go our separate way."

"Are you sure, Sister?" the Snake Girl said. "Even if you're strong, you aren't at the Transformation Phase. We are some of the weakest Monster Girls inside the Labyrinth. Shouldn't we stick together?"

"Let me ask you: are those two your close friends?"

"We've been through frost and flame together." The Snake Girl perked up. "You can trust them to guard your back."

The Lily Girl blushed as she tucked the Snake Girl, trying to stop her from complimenting too much. The Beetle Girl faked coughing as she listened to more praises, looking at Iris, trying to get praises out of her too. Their synergy was above average; if they focused as one, their power would rival a lone Transformation Phase Monster Girl.

"But can you all trust me to guard your back and that I will know when to retreat and when to advance?" Iris said. "I might be strong, but if we aren't compatible, we would be undermining each other instead of empowering ourselves."

The Snake Girl wanted to persuade Iris, but she couldn't think of anything to counter that argument. When she came back to herself, Iris had already turned around and descended further into the spiral tunnel, her back disappearing into the corner.

Though she wasn't strong, the black-scaled Snake Girl was a specialised mage in her past life. Her pitch-black pupils radiated a mysterious aura as her gaze lingered at Iris's dispersing presence. Though she didn't know about Iris's power and origin, she could feel an ambiguous air permeating that slimy body.

Iris was someone who had great potential, someone who should be befriended and helped to blossom.

"Let's catch up with her," the Snake Girl said. "I can sense that she's a strong one. If we help her, we might gain unexpected rewards."

The Snake Girl slithered around the corner, but Iris had already disappeared into the spiralling depth. The group then quickly descended, trying to catch up with her. No matter how fast they went, they could never see her silhouette and had to give up after they exhausted themselves.

Once silence returned to the tunnel, Iris emerged from the darkness around the corner, coming out of a small rift on the wall. The Shadow Heart Core contracted and expanded as she willed, turning into a speck, letting her hide inside the crack. The emblem was slim enough to fit the narrow space.

Iris sighed and resumed her slow descension. While it would be great for her to join them, she wouldn't want to risk exposing her secret. Either they would get greedy, or the knowledge would implicate them. Joining them also went against her main objective. She couldn’t risk increasing more uncertain factors.

The ominous air gradually intensified as Iris approached the lowest Layer, but she had already gotten used to it. The amounts of Transformation Phase Monster Girls greatly increased as she descended farther. Their average power exceeded what Iris had seen inside the Main City, though they lacked the fineness and the carefree air. Their hardened look and savage disposition reminded Iris that she was heading into the battlefield, not a playground.

She also encountered more groups that wished to recruit her, but they didn't persist once she refused them. It would only waste everyone's time if they persisted. Unlike that Snake Girl, they didn't want to stick to Iris; they were just good Samaritans who tried to help a lone Monster Girl.

Though she was confident in her power, Iris wasn't sure if she could handle a Transformation Phase Monster Girl. She only experienced their might once. Penlarin and Warnuli easily restrained her. If she were as powerful as now, she might be able to resist, but there was no telling how high in the totem those two stood.

The Puppeteer Legacy Ground would be a perfect place to test her power, to see the fruit of her result, and to witness the power of the world at its height.

After spending a few hours inside the spiralling tunnel, Iris stepped out of the cave, finally walking on the even ground. The world in front of her stretched across her view like an unfolding paper, revealing a scenery unshackled by the narrow ceiling and stiff rocky tunnel walls.

In contrast to the Main City Layer, the lowest Layer lacked the cheerful festive air. Like an unwavering statue that towered against the flow of time, the surrounding became tainted with the dull grey of ashes and dust, coating the spares trees with dim sparkles which flickered as the light fell on them.

Iris stepped on the dusty path, creating a soft puff of wind that scattered the ashes around her. They resembled the orange fall leaves, fluttering in the air, struggling for a fleeting moment before accepting their fate. A sense of melancholy permeated the atmosphere, seeping into Iris. She sighed and condensed her membrane, keeping the toxic soils out of her fluid body.

Aside from the abundance of ashes and grey, the Ashes Forest Layer had a lot of Aquatic Monster Girls. They usually only resided in a few underwater Layers, but the Puppeteer Legacy Ground prompted them to come onto the land. Their fishy yet lovely odour tucked Iris's attention and captured it with their colourful scales and their alluring texture.

Iris's eyes flashed as she peeked at them. Because most of them didn't have legs, they slithered on the ground, leaving a wet trail behind. Their tail looked slippery and sensitive, but their naughty, nasty vibe prevented Iris from going near. She wasn't the only one eyeing, for they also eyed her; a Liquid-Body Monster Girl was the best match for the Aquatic Monster Girl.

Iris didn't want to get into trouble, so she hastened to the monumental structure in front of her. The double gates pierced the layer's ceiling. Its walls stretched across the Layer, creating an oppressive feeling of confinement. It was the entrance into the Puppeteer Legacy Ground.

Looking at the massive structure and its components, Iris found herself thinking about the past. The aesthetic of the gates bloomed as the gigantic gears embedded in them slowly turned, booming out mechanical sounds, ticking like clockworks. Even from afar, Iris could tell that the technology required to create this building had surpassed the convention of this world.

From the presence of the Foreign Existences, the creator of the Puppeteer Legacy Ground might have a connection with the other worlds. The unifying design of the gates was a mix of the futuristic world and the ancient Victorian era. Either it was inspired by her world, or her world was inspired by the great beings who originated the aesthetic.

"So this is one of your plans," Iris murmured. "How far have you seen into the future? Do I really have a choice?"

Heavy thoughts circulated her mind as Iris arrived at the foot of the gates. A simple wooden fortress was watching over the entrance. The guarding Monster Girls wore a myriad of equipment, but their identifying feature was a crystal badge with a symbol of the Crystal Dragon Lord, Corane.

They didn't take any payment or fee but only watched for any infiltrating Subterranean Creatures. Though they were strict, their playful manner had made the procedure a carefree experience. The other Monster Girls easily went through.

Iris took a deep breath, held onto the document given by the First Hall, and walked towards the fortress. The appearance of a lone Monster Girl wasn't too uncommon, but Iris was only at the Metamorphosis Phase, which was a rare occurrence.

"Sister, are you alone?" a guard, a Mineral-Type Monster Girl, said. "The Legacy Ground is a dangerous place, but I reckon you already know that. Still, are you sure?"

"I came from the Main City Layer and had already prepared everything."

Iris handed the document to the guard, who examined it for the correct seals and information. After verifying the authenticity, she nodded and took out a small case. Inside the glass layer, a green glowing crystal floated, radiating a soothing warmth that combated against the dull grey of the surrounding.

"Sister, take this with you. It isn't much, but you can break it to conjure a barrier to protect your life. You're still young and inexperienced, so you might need it."

Iris was about to return the item, but the guard stared at her and smiled. If she didn't take it, she wouldn't be able to get into the Legacy Ground.

"Thank you, Sister," Iris said. "I can't leave without repaying you, so please listen to me for a moment."

Iris stepped forward and took out a silver badge from her inside. The dignified aura enveloped her being, sweeping outwards with a majestic pressure that momentarily instilled colours into the dull layer. The guard shivered as she fell on her knees, but Iris caught her arms and leant to her ear.

"My name is Iris, a wandering Slime Girl. You can tell the Garden of Splendour in the Main City about me. They'll appropriately welcome you."

Winking at the guard, Iris put the badge inside herself and strolled to the gap between the enormous gates. The surrounding guards parted for her, falling to their knees as they recognised the symbol on the badge. The guard who gifted her a protective item just sat on the ground, repeatedly blinking, staring at Iris's receding back.