I managed to save Noir but the poison had affected Blanche as well as the woman in black and I had to go after the [Void Venom Cult] to find an antidote. After a quick change of clothes, I prepared to infiltrate the cult's headquarters.
I managed to get in but the sights inside were truly horrifying. The most cruel experiments on humans and rare beasts, my bond Nero's mother rotted in a cage inside. By the time I reached the innermost area, I was filled with rage at their disgusting disregard for life.
I let my sword loose and a pile of bodies formed at my feet. Including the head of their leader. In the end, I absorbed their greatest treasure and gained full mastery of the poison god's methods. With the antidote in hand, I returned to the [Black Cloud]'s underground city and healed both Boanche and the boss whom I learned was Natalya.