While he was human, Samhain was betrayed by his peers and was mutilated, almost left for dead. He was lucky at that time that an angel took care of him, to put him back on his feet. This angel had been betrayed too, and she chose to impregnate Samhain's body by making him gain her gifts. Since that time, he has been in her service in a way and is grateful to her.

Samhain and his angel want to eradicate the world of its aberrations, of all the oddities that have gone wrong like Gray. To achieve this, they need two things: a map that is inside a special book, in the library of a famous author; and a vessel - Gray's body - for the angel to regain her freedom.

Samhain had first sent a vampire killer to convince Ivory to retrieve this book, but he failed his mission, defeated by the Roggenwolf. So, he chose to take care of it himself. He has been watching Ivory for a long time and is waiting for the right moment to intervene, a Halloween party. Disguised, like all the guests, he easily enters and finds Gray alone in a room of the house. Before she can react, he cuts off her head. As he picks up her body, Vince enters the room and witnesses what has just happened. Samhain escapes with Gray's body through the roof but tells Vince to tell Ivory that he will wait for her.

Gray - her head that still manages to talk - tells Vince to go get Ivory. Ivory is later found with Gray's head in a forest, following Gray's directions as he senses Samhain's presence. The ground opens and they fall into a very large cavity under Santo Pedro. Grey's body is seen attached to the center, by what looks like spider webs.

Samhain slowly emerges from the water and addresses them. He explains that the world is threatened by the children of a benevolent goddess, one of the protective Gods of Santo Pedro in the past. The angel inside Samhain was present at that time, which dates back more than 400 years. Samhain will open his belly to show the head of this angel inside him, before continuing. The angel had also believed in the goodness of these Gods, but when the city was invaded and pillaged, they did nothing to protect them. They abandoned the inhabitants to their fate. This is why they now want to destroy anomalies like Gray and her ilk.

Samhain rips Gray's head from Ivory's hands and throws it into a stream of blood, to be alone with Ivory. He makes him one last proposition: if he agrees to give them Gray's body, Samhain's angel will be able to separate him from his Roggenwolf.

Ivory refuses again and frees Gray's body by shooting the bonds with his weapon. Gray's body will eventually find its head in the stream and with the help of the power inside her (her chimera), she’ll defeat Samhain. Before disappearing, Samhain tells her that the defeat she has just inflicted on him is what awaits the world, that it’s her destiny to destroy everything. Gray is furious and rips the angel's head from Samhain's body to throw it very far away.

Samhain will return a few weeks later, even stronger. Rid of the angel in him, who was ultimately a demon, he no longer needs it. He now wants Gray's body for himself.

In an amusement park, he will kidnap Vince and rise into the city sky. Gray flies to Vince's rescue by bringing Ivory with her. Samhain had the upper hand on her and Gray was forced to let her chimera take control of her body. Gray thus became even more powerful and was able to defeat Samhain once again, wishing to have annihilated him definitively.