Isaac, alongside Genthru, Nomdieu, Assam, and Nickes try and recruit new players Abengane, Puhat, Biscuit Krueger, Gon, and Killua to Nickes' Alliance. The group manages to convince Puhat and Abengane to join, but fail to convince Gon, Killua, and Biscuit to join for their own respective reasons.
Although a supposed senior member of the alliance group, he and fellow alliance member Nomdieu were left out of a conversation had by Genthru, Assam, and Nickes. It's uncertain if Isaac was at the alliance base when Genthru revealed himself as the Bomber, he along with the rest of the alliance, aside from Abengane and Cuzco all die as the bombs set onto them all detonate simultaneously. Isaac's name is mentioned on Gon's binder, when he looks to see which players are dead or alive.