Elliot and the priestess left Cain to talk to his children. Apparently, Cain was over 60 years old, but Infernals do not age like Terrans. They have longer lifespan and older age of maturity. Seeing the father and his children interacted made Elliot and Geneva crossed Cain out of their candidates.
They will never going to convince him since he doesn't want to leave his family behind.
So they spent an hour more together, thinking of a person who would rule Inferno. Elliot's other friends were busy settling the people into their homes while Connor was nowhere to be seen.
Their brainstorming took a while considering that unlike the other realms, Inferno couldn't be ruled by choosing a leader through voting. Someone with power, who is unfit and tyrannical, will threaten as much people as they can to vote for them, taking the throne in the process. And as much as possible, they had to stop another version of Monstrum.