Initial Stage

A Gu Master raises cultivation inside a rank by spending primeval essence to nurture the aperture walls. At initial stage the walls are light barriers, also called light walls or a light membrane, ^{ch. 33} thin, flickering white light. ^{ch. 212 ch. 230} Advancing to middle stage turns that light barrier into a water barrier. ^{ch. 33} Crossing from rank one peak stage to rank two initial stage is a large-realm break, not another small-realm step. ^{ch. 90}

Within a rank, higher stage means darker, more durable primeval essence. ^{ch. 80} Green copper primeval essence at rank one initial stage is jade green. Ordinary academy students nurture the aperture with that initial stage store. A Liquor worm can refine it up one small realm into middle stage essence without the Gu Master first becoming middle stage in cultivation, and that denser essence nurtures the wall and powers Gu more efficiently. ^{ch. 34}

At rank two initial stage, red steel primeval essence is light red. ^{ch. 145}

White silver essence at rank three initial stage is light silver, only thinly silvered. ^{ch. 312}

Purple crystal essence at rank five initial stage is light purple. ^{ch. 379}

When a Gu Master breaks a large realm, the old peak stage crystal wall shatters and a new light membrane appears. That light membrane is the mark of the next rank’s initial stage. ^{ch. 475}

The other three small realms are Middle Stage, Upper Stage, and Peak Stage. The full rank ladder is on Ranks and Realms. Essence by rank is on Primeval Essence.