Death Heir
After moving the Death Worm Immortal Cave a good distance away, Ryu realized that it had stalled. He would have liked to move it further, but there were two main issues.
Firstly, it hadn't been maintained in hundreds of millions of years. Its joints were stiff and its moving parts were definitely in terrible condition. Secondly, movement required energy. After shifting the Immortal Cave's place several dozen miles away, what remained of its energy was completely drained.
Ryu would feel very foolish right now if it wasn't for the fact the Ruin Core allowed him to teleport directly to the closest point on the surface. If not, he would have to dig his way out…
Because of the Immortal Cave's structure, it was able to chew up dirt from the front and pass it to the back, perfectly concealing its trace. But, this also meant that without the Ruin Core, one could be buried alive if they weren't careful enough.