The stone sealed itself behind him with a soft, grinding sigh, as if the ancient ruin was relieved to be returning to its solitude. Leo paid it no mind. His entire world had narrowed to the space between his own form and the hovering bronze compass. It bobbed gently in the air ahead of him, its needle a sliver of unwavering purpose in the shifting, deceptive gloom of the Deep Dark Forest.
This part of the woods was different. The air was colder, tasting of damp rot and old magic. The trees were no longer merely twisted; they were grotesque, their branches like the gnarled fingers of buried giants, clutching at a sky they would never see. The usual, skittering sounds of lesser monsters were absent, replaced by a profound, watchful silence. It was a silence that felt heavy with age and intelligence, not fear. The creatures here didn't flee because they were terrified; they didn't approach because they were assessing.
Leo, blissfully unaware of the subtle shift in the ecosystem's demeanor, focused on the simple act of travel. He no longer oozed or glided. He found he could simply will the earth to carry him. A platform of packed soil and intertwined roots would detach from the forest floor and slide forward, carrying him smoothly over treacherous ravines and through thick, thorny brambles that parted before his terrakinetic influence. He was a passenger on a landship of his own design.
[The energy signature of this region is denser by a factor of ten,] [Sage] noted, its voice a calm counterpoint to the oppressive atmosphere. [The flora and fauna exhibit higher magical integration. Caution is advised.]
[It's quiet,] Leo thought back, his perception of "caution" now permanently skewed by the understanding of his own immortality. A threat was just a temporary noise.
After what felt like hours, the compass needle began to quiver, no longer pointing straight ahead but dipping downwards, towards the base of a colossal, sickly-looking tree whose trunk was wide enough to contain a small house. Its bark was the color of bleached bone, and a faint, phosphorescent moss clung to it, casting a pallid, blue-green light. The needle pointed directly at a fissure in the trunk, a dark, narrow opening that led into the earth.
[Destination proximity is high. The source of the compass's alignment is subterranean.]
Leo dismissed his earthy transport and stood before the fissure. It exhaled a breath of air that was frigid and carried a strange, metallic tang. He peered into the darkness. His slime body required no light to perceive his surroundings; he could feel the shape of the tunnel through the subtle vibrations in the earth and air. It descended sharply.
Without hesitation, he entered.
The tunnel was not natural. The walls were too smooth, too regular, carved by tools or by a power that cared for precision. The descent was long and spiraling, taking him deep into the bedrock of the continent. The air grew colder still, and the metallic scent strengthened, now mixed with something else… something ancient and dry, like a tomb that had been sealed for millennia.
The tunnel finally opened into a vast, cavernous space. The ceiling was lost in darkness, but the cavern itself was illuminated by the same phosphorescent moss that grew in thick, pulsating patches on the walls. And in the center of the cavern lay the source of the compass's pull.
It was not a treasure chest or a magical artifact. It was a skeleton.
The bones were immense, belonging to a creature that would have dwarfed the Forest Titan. A long, serpentine spine coiled around itself, and a massive, horned skull rested on the cavern floor, its empty eye sockets staring into eternity. The bones were not white, but a deep, lustrous black, like polished obsidian, and they seemed to drink the faint light from the moss. Scattered around and partially embedded within the skeleton were shards of a bronze-like metal, corroded and broken. The remains of armor, or perhaps restraints.
『Like this:

』
The compass in Leo's grasp shuddered violently, then its needle spun in a frantic circle before going completely limp. Its purpose was fulfilled. It had led him to this long-dead leviathan.
[Analysis: Skeletal remains of an unidentified draconic or serpentine entity. Age estimates exceed this unit's chronological parameters. Cause of death: undetermined. The residual magical energy is immense but inert, locked within the ossified structure.]
Leo moved closer, his form glistening in the eerie light. He felt a profound sense of age here, a stillness that made the ruin above feel newborn. He reached out a pseudopod, not to absorb, but to touch one of the colossal ribs. The bone was cold, harder than any stone he had ever felt.
As his gelatinous body made contact with the obsidian bone, something shifted.
A jolt, not of energy, but of information, lanced through him. It was not a memory, not a sight or a sound. It was a pure, raw concept. The concept of Flight. Not the crude, physical act of wings beating against air, but the transcendent principle of defying gravity, of claiming the sky as one's domain, of moving through an ocean of air with the same effortless grace he moved through earth.
The concept burned itself into his being, a new, fundamental truth.
[Skill Acquired: [Aerokinesis - Foundation].]
[Sage]'s notification was swift. [Host has interfaced with a residual concept imprinted upon the entity's remains. This is not energy absorption. This is… epistemological assimilation.]
Before Leo could process this, a low, grating rumble filled the cavern. It was not the sound of stone, but of something old and dry being forced to move. From the shadows behind the great skull, a figure unfolded itself.
It was not a monster. It was a being of polished bone and woven, petrified roots, shaped into a vaguely humanoid form. It stood twice Leo's height, and in its hand, it held a scythe made from one of the leviathan's own giant ribs. Its head was a smooth, featureless orb of bone, but two pinpricks of cold, blue light ignited in its center, fixing directly on Leo.
It did not speak. It did not roar. It simply pointed the rib-scythe at Leo, and the intent was clear: You desecrate this tomb. Leave, or be unmade.
For the first time since his reincarnation, Leo was facing a guardian. Not a mindless predator, but a sentinel. A being with a purpose beyond eating and breeding. It was a new kind of puzzle.
The Bone Sentinel took a step forward, its movements silent and fluid, and the temperature in the cavern plummeted