Chapter 76 of Hell's Paradise: Jigokuraku.
As a child, Ju Fa was told by Rien that he and Tao Fa were special in that they were born as two of a whole. Since then, Ju Fa developed the urge to protect Tao Fa and came to Mei for answers. Mei tells him that it was natural for him to care for her since she was his partner, the fact that he is able to imagine the pain she feels. Ju Fa then notices a change in Rien after he introduces the five Tensens to the Hōko, explaining that they are allowed to use them to replenish their Tao. He then assigns them their training regimens in achieving immortality, with Ju Fa and Tao Fa being assigned Bōchū Jutsu. During one of their training sections, Tao Fa expresses her pity in using the Hōko to replenish their Tao. Ju Fa agrees with her and causes Tao Fa to feel happy that he understands how she feels. After a few centuries had passed, Ju Fa becomes frustrated that the Hōko are on the verge of extinction due to their Arborification and how Rien and Xu Fu are not trying to fix the problem. Gui Fa suggests using the humans from the mainland as another source. Mu Dan tells him if he did not like the idea then they are fated to die. After remembering everything that Tao Fa has gone through, Ju Fa becomes angry and suddenly starts to imagine the Tensens smiling, fearing that either he or the others have gone mad. Later, he walks down to the floodgate and sees that Mu Dan and Tao Fa are preparing to send out an Arborified Hōko to lure in humans to the island, having no other choice but to use them as another Tao source. Ju Fa asks Tao Fa if she was okay with doing this after remembering her past stating about the Hōko. She then turns around with a smile answering yes and asked if she was crazy. Ju Fa comforts Tao Fa and tells her that she was not crazy, saying that the humans are to be treated lower than livestock. Back in the present, Ju Fa and Tao Fa transform into their Kishikai after merging together.