What happens exactly with the Balseraph of Kronos Attunement?
The Balseraph is bound by everything in the Resonance/Dissonance sections of the Choir description plus any relevant text in the Mechanics section. For example, Bob the Balseraph can emulate a Kyriotate. So Bob is bound by all the restrictions of a Kyriotate (harming the host, etc). Note that since the Manner and Appearance is not included in the Balseraph of Kronos’ Attunement, the “stunning” affect of Kyriotates in celestial form is not available. One note is that with the Kyriotate Resonance, they can still buy vessels normally, but can only use ’em when not possessing someone (Infernal Player’s Guide, p. 29). Plus they emit normal disturbance when their vessel manifests or is put back into storage.