Formation path immortal material

At ordinary formation path levels, Gu formations can rest on Gu materials as well as Gu worms, but the user can only draw on the dao marks inside the immortal materials; after a long time those immortal materials are destroyed. Formation path great grandmasters go further and can also use surrounding environmental dao marks. ^{ch. 1333}

With formation path grandmaster attainment, Fang Yuan has to use immortal materials to set up immortal formations. Only formation path great grandmaster level can set up an immortal formation from natural dao marks of the outside world alone. ^{ch. 1611}

Using dao marks inside immortal materials to unleash killer moves is not rare, and grandmaster formation path Gu Immortals are able to use immortal materials to set up formations. ^{ch. 1817}

At grandmaster formation path attainment, Fang Yuan cannot use natural dao marks and must use immortal materials; the immortal materials expended on that work are his greatest spending there. ^{ch. 1899}

Being able to use immortal materials to set up formations marks formation path grandmaster attainment. Ordinary formation path Gu Immortals need Immortal Gu to create immortal formations, while a formation path grandmaster only needs to use immortal materials. That same reliance makes immortal materials the greatest limitation when the stock runs low. ^{ch. 1904}