Dark soft silk

Constructing coiling thread caves needs a Gu formation plus rank six immortal material dark soft silk and rank seven immortal material regret water rocks. Fang Yuan plans that work once Mount Snail funds leave him spare resources for a large scale expansion of his second major resource. ^{ch. 1316}

Dong Fang tribe’s method for coiling thread caves sets up a Gu formation and requires dark soft silk together with regret water rock, so ordinary spiders can qualitatively transform into regretful spiders. Fang Yuan gathers both materials by paying a large amount of immortal essence stones and some other immortal materials, then turns to setting up the Gu formation itself. ^{ch. 1327}

Fang Yuan tries to modify the coiling thread cave Gu formation to raise regretful spider production eightfold, but the final step of the plan proves unsolvable. He abandons that modification, concluding he can only find a new one. ^{ch. 1330}