He had been too reckless in his advance. He hadn't been watching, he hadn't even seen where her arms would be or how they would be able to grab him before he could plunge that arrow deep into her skin. Before he knew it, one hand had twisted his away and the other grabbed him at the neck, causing the beast to choke and sputter in her grip. He struggled; his fury still seethed through him, vicious jaws snapping at her, hungry for skin, for anything that he could get. It didn't matter how much he tried, he would fail to reach her; it didn't matter how many times he reached for her with his extra appendages she would always evade his grasp, and as soon as her voice touched the air, the beast felt a looming sense of disaster.
He grunted as she pushed him against the wall. His jaws ceased gnashing, realizing now that she had him and she was going to do everything she could to destroy him like she'd destroyed his other half. Instead of trying to tear her apart, he was clawing at her, pulling and pushing away from her, trying to escape. He saw her jaws unhinge and rows upon rows of reptilian teeth glisten in the pale light of the tunnel, and then pain. She bore into him like he was a feast, and the monster let loose a strangled cry, snarling and howling and choking as she tore chunks with both her hands and teeth. Pain, pain, pain. Bits of his flesh tore away with ropes of inky black blood, severing tendons and ligaments that wove through his neck, shoulders, and chest; where a vivid green eye once sat, the socket had been torn open and the eye bled furiously, seeping from its cradle. Blackness swelled up from his throat, between his lips, smearing across Jupiter who sunk her fangs so deep into him that his life began to flicker - in, out, in, out in out inoutinoutinout
That brief moment of hesitation was all they needed. and suddenly everything came clear.
The beast stopped struggling, limp against Jupiter. They could feel it now, they could feel everything. What little life remained in that serendebite began to quake, energy pouring out from the stone as it lay nestled in the armor. What little memories were attached to the armor began to manifest into an entity. Something living. It reached out, called for the beast to return, and so he did. His crooked, broken mouth still found the strength to twist up into a wicked grin, just barely, before the solid mass of blackness that made him began to melt into something... intangible. Aqueous shadows slowly slipped out of Jupiter's grasp, draining down the wall and away from her. Bright green faded, overcome in the tendrils of wispy darkness as they all surged towards the pile of armor, and from it a glow of pale peridot.
Without warning, the relics came to life. A cloud of shadow and misty green spun up from the pile, twisting among itself like a whirlwind of colour and the absence of light. A soft wind wrapped itself around the room, heedless of the ones within. The wind grew stronger and stronger, and the whirlwind grew larger. Faces manifested within the vortex of darkness, some of them contorted, others clear. Snarling, laughing, wailing, all kinds of emotions grew within the whirlwind as the armor lifted and vibrated in the pressure of the whirlwind. Appendages jerked out from the swirling twister, filling the boots, sliding into the gauntlets and the pauldrons, through the chest piece. Every object littered across the floor of the tunnel shook, jittering away from the walls and towards the vortex. The gleaming piece of peridot seemed to situate itself in the heart of the shadowy mass, while the serendebite hovered at its peak.
Forms began to take shape. Fronds of shadow swept across a hulking body with dual limbs; legs that glitched in and out of the armor, arms poised, reaching, grasping and clawing, and a head. A head with four eyes, each glowing ominous green, and two jagged mouths that opened atop one another, pointed teeth encasing lime gums that glistened, hungry - the shriek of a banshee erupted from the massive shadow monster that towered over Jupiter.
The two forms separated. One of them stepped out of the mass, taking the armor with it; the other's body became solid again, dropping to the ground, the familiar anatomy of the beast lay sprawled across the empty floor. But the second...
The second was furious.
Mirroring the beast in size and shape, they stared down at Jupiter with clawed hands flexed and gaping maw unflinching. Then, they lunged, intending to consume the centaur whole.