Wait, I'm a Magical Tree!?

Stone vibrates to a certain frequency, a harmonious frequency that aligns with the world tree above. Shimmering slightly from all the pulses of Prismatic energy flooding it, the walls of the narrow cave tunnel are still Barren, but it's alive. Rich in nutrients and water, some roots of grass can be seen barely growing.

The four spirits float through the still barren cave system, feeling unknown energy coursing through this underground labyrinth. Campfire, Twinkle-Star, Geo, and Wispy levitate together, their magic-based bodies staying close together. Akin to a group connecting their backs in a defensive position, they've always done that when exploring.

The Ul'tan forest became a dangerous place, the residual Dark Mana that stained it attracted monsters. This formation which they called the "Bunch-up" formation, worked well this far so no need to change it. They go deeper, and more and more the energy flowing through here feels like currents. Crashing against them gently, like a slow-moving river. They venture deeper, the tunnels expanding out. Soon crude architecture appears, along with what looks to be circular discs on top of columns of stone.

Campfire, Twinkle-Star, Geo, and Wispy know exactly what this is. It's a Mana Lock.

Campfire: "Oh, it's this place again. . ."

Geo: "Damn, coincidences sure are frightening. . ."

Wispy: ". . ."

Twinkle-Star: ". . ."

Like all sentient life, races want to survive. So they advance, accumulate more knowledge, and learn how to make tools and weapons to fight against existential threats. Spirits, Fairies, and Dryads were no different. They also had to survive, and they created technology as well. This "Mana Lock" was their safety net. A Mana entangler, it tangles Mana types together. Creating a unique "Mana code", and to match and unlock the Mana Lock, you must have a physical miniature disc with the same Mana code encoded within it.

Once the Mana Lock recognizes the Mana Key, it unravels and allows entry. But seeing the defunct piece of tech rotting in front of them. It refreshes the memories of those torturous centuries long past like a worm refusing to let go of its host. Living rent-free within the mindscape of the four.

Wispy: "It's our birth-place guys. . ."

Geo: "Tch. . . Ironic really, all that wandering and looking for ways to survive all lead back to here. How wonderfully ironic."

Twinkle-Star: "I-I don't feel any overwhelming dark energy, it's all. . . gone."

Campfire: "We couldn't even enter this place without feeling like we were dying, what changed?"

Geo: "Isn't the answer obvious Campfire? The big guy up there did it. The World Tree."

Campfire: "R-Right."

Campfire felt embarrassed for asking such an obvious question. Wispy floats near the entrance to Rei'uz, the name of the long-dead city of the spirits. Countless thoughts whirled within her like a storm, all of her lamenting thoughts about her uselessness at what happened to her home run amok.

Geo floats beside her, feeling the self-loathing emanating from her partner.

Geo: "I know that feeling partner, it's not your fault."

Wispy: "It is. . ."

Geo: "You didn't mean to lead them here."

Wispy: "It doesn't matter if I did or didn't mean it. It's still my fault!"

Geo: "But—"

Wispy: "Geo. Let's. Just. Stop. Here. . . I don't want to talk about it. . ."

Wispy quickly floats away into the city. She is ignoring the pleas to stay close to her friends. Geo, Campfire, and Twinkle-star follow Wispy, crossing the threshold into Rei'uz. Meeting them on the other side of the door is a vast space, filled with cracked buildings, floors, and walls. Underneath the cracked floor a giant chasm groans.