Val's playing host to a demon child she basically adopted. She feeds it souls and it keeps her alive while she runs her rebellion. Granted, the demon is still pretty young so it's not exceptionally strong yet.
https://toyhou.se/2408024.kieth#8382093 Kieth is host to a parasitic void demon(the jacket) named Tohu-bohu. It partially consumes its prey then makes them go about their lives as normal as it feeds on their emotions and soul, anything to help from feeling like the empty void that it truly is. Occasionally possesses its victims and leads them into strange or dangerous areas.