Blood Skull Gu

The Gu first appears when Problem Nipped in the Bud Gu pulls a crystal skull from First gen Gu Yue’s aperture, and Lord Sky Crane names it Blood Skull Gu on sight. ^{ch. 193} It is one of the true inheritances of the Blood Sea Ancestor, originally held by Lord Sky Crane before First gen Gu Yue seized it. ^{ch. 195} Fang Yuan later snatches and refines it during the Qing Mao Mountain fight. ^{ch. 197}

Appearance

It looks like a crystal skull of a child that can fit on a palm, filled with reddish bloodstripes. ^{ch. 193} After it drinks its fill, the blood stripes on the crystal skull turn brighter, and blood enters through two empty eye sockets. It can open a tightly shut mouth. ^{ch. 194} In the aperture it can lie deep in the primeval sea with bright red blood light flashing on its surface. ^{ch. 202}

Beside the Heavenly Essence Treasure Lotus, the text calls it the demonic blood skull Gu: a blood colored skull with two eye sockets glowing with purple flame. ^{ch. 273} Blood skull Gu is paired with heavenly essence treasure lotus and Spring Autumn Cicada as an example of an evil and bizarre form. ^{ch. 278}

Rank and path

It is rank four. ^{ch. 194 ch. 198} No cited early chapter assigns Blood Skull Gu to a named cultivation path in its own words. It is introduced as a Blood Sea Ancestor true inheritance, not as a labelled path Gu. ^{ch. 195}

Effect

First gen Gu Yue tells Lord Sky Crane that Blood Skull Gu can purify the blood of relatives killed and pour it into the aperture, upgrading aptitude. ^{ch. 195} First gen Gu Yue uses it that way on Gu Yue clan members inside the blood shield, absorbing blood through the skull’s eye sockets until the rank four Gu is glistening red at its absorb limit, then having it vomit a blood fountain into his body and aperture. ^{ch. 194}

Fang Yuan repeats the same process after he takes the Gu. After about a hundred kills the crystal skull turns blood red; activation sends a fragrant blood stream over him and into his aperture. One early rise takes him from 43% C grade aptitude to 53%, then to 63% B grade, and after repeated baths his aptitude climbs past 90% A grade, while his cultivation falls because Blood Skull Gu overrules his Stone Aperture Gu and undoes that Gu’s forced rank climb. ^{ch. 198}

It is a Gu that can change aptitude, and it has already lost worth for Fang Yuan once almost no blood relative remains. ^{ch. 230} It is a divine Gu for raising geniuses for a clan, still valuable to others even when it is useless to him. ^{ch. 302}

Feeding

Blood Skull Gu requires blood. Fang Yuan stores fresh crocodile blood in the tusita flower to feed both Blood Skull Gu and Blood Moon Gu. ^{ch. 205 ch. 202}

Fang Yuan’s early use

He grabs Blood Skull Gu and Yin Yang Rotation Gu as their seal fails, then uses Spring Autumn Cicada’s aura to refine the rank four worms at once. ^{ch. 197} He and Bai Ning Bing slaughter Gu Yue clansmen inside the blood barrier so the Gu can raise his aptitude instead of First gen Gu Yue’s. ^{ch. 198} In Shang clan city he still keeps the Gu in his aperture next to heavenly essence treasure lotus, but judges it useless for his own path unless he invests the time to nurture descendants, and notes it remains a Blood Sea Ancestor inheritance he could trade. ^{ch. 273}

Blood Sea true inheritance list

Used on Chang Ji You

Immortal Gu plans

Blood skull Immortal Gu