The Fractal Keystone manifests as an infinitely recursive three-dimensional pattern that appears differently in each realm. It emits a harmonic resonance that strengthens when the Perfect Line is thrown near it, creating visible interference patterns. The keystone can only be manipulated through precise mathematical understanding of its patterns, resisting all physical force while responding to correct geometric inputs.

It functions as a structural anchor that temporarily stabilizes weak points in reality during Convergence events, preventing complete dimensional collapse at critical moments.