Patriarch Blacksoul is one of the several minor antagonists in I Shall Seal the Heavens. He is the patriarch of Blacksoul Society, the sect that captured a soul piece of Chu Yuyan's. He faced off with Meng Hao when the latter imposingly demanded the soul back.
Seemingly embodies the very definition of his sect, overbearing and has no qualms using even dead bodies to suit his own purpose.
Confronted Meng Hao when the latter attacked Blacksoul but was unable to prevent the death of all the disciples. Enraged at the extermination of his sect, he offered to be a slave to whoever succeeds in killing the culprit, Meng Hao. An offer so tempting that Heavengod Alliance almost expended all their resources in hunting down Meng Hao.