Peak Stage

Peak stage walls are a crystal membrane: white crystal walls, ^{ch. 86} with ethereal, pure radiance. ^{ch. 230} To leave peak stage for the next rank, the Gu Master must break that crystal wall completely so the aperture can evolve through its destruction. Cracks alone are not enough, and a wall that is only damaged can heal. ^{ch. 90}

Higher stage inside a rank darkens the essence and raises how much work a given share of the sea can do. Green copper primeval essence at rank one peak stage is black green. At rank one, ten percent of that black green store matches twenty percent dark green, forty percent pale green, and eighty percent jade green, so peak stage essence stretches far further in battle than an initial stage store of the same percentage. ^{ch. 80}

By rank two peak stage, red steel primeval essence is dark red. ^{ch. 145} White silver essence at rank three peak stage is snow silver: snow white silver. ^{ch. 312} Yellow gold essence at rank four peak stage is true gold primeval essence; one further step is rank five initial stage light purple essence. ^{ch. 424} Purple crystal essence at rank five peak stage is crystal purple, clear like liquid crystal. ^{ch. 379}

At rank five peak stage, Gu Masters stand at the peak of the mortal world, spoken of as emperors among Gu Masters. For many at that height, the stated aim is to leave the mortal range and charge toward rank six. ^{ch. 373}

When the peak stage crystal wall breaks completely, the crystal fragments fall away and a new light membrane of the next rank’s initial stage takes their place. ^{ch. 475}

Initial Stage, Middle Stage, and Upper Stage complete the set. The full rank ladder is on Ranks and Realms. Essence by rank is on Primeval Essence.