Ruby's father and a former Stea Republic Army Officer. He has betrayed Stea Republic and become a treasure hunter to track down the Legendary O-Part. Died in official record but is later revealed to be a traitor and commander-in-chief of the Zenom organization. Jack has the nuclei of both Devil No. 5i - Asmodeus and Devil No. 6i - Belphegor within him. He has shown great control of both and is able to release to any percent he wants, but to use both he has to split the percent between them for example in chapter 73 he released Asmodeus at 70% and Belphegor at 30%. He is also able to combine the powers of both for different attacks. In chapter 74 it's shown that the nuclei have greatly effected Jack's personality without someone there to keep it in check, and reverts fully back to the loving father Ruby remembers as they are taken by the fused Kabblah shin. It's also shown that he's had at least one nuclei in him since he intentionally left Ruby when she was a child, and was partly the reason he even left. He was sucked into Shin to help start Armageddon which was stopped by Jio. Inside shin to save the world with the help of Jio, Cross, Zero and Ruby, they warped shin away from earth just as night fell disappearing into the void of space.
Vova
