Kapitel 1416: How To Grow Your Seed.

The pot has reached its limit, so the soil is removed from the pot and tempered. The pot is also smashed, and liquid is added to it for it to become malleable. The remnants of the pot and the tempered pot are then combined and remolded to form a superior vessel. 

This process is the breakthrough to transcendence. Some potted soils fail this process. Some succeed. The result is a malleable vessel capable of expanding.

It is a vessel with both the properties of rigidity from the pot and the ability to be increased that the soil possesses. In doing so, a previously untapped potential is accessed. But they have also lost the ability to grow larger by imbibing mana.