Remember Kellhus quote about the Gods and how the No-God is mucking with history.
The Gods and their agents inhabit a world where they are doomed to succeed (WLW, since the Gods are atemporal), then transition without noticing to one where they were always doomed to fail when the No-God thwarts them.
It isn't that the existence of atemporal beings denies free will, it is that free will (in the form of the nondeterministic No-God and its slaves) transforms those eternal beings, makes them over again every time they interact.
The Ajokli who possessed Kellhus did so from beyond history, in a world in which he had/would always possess Kellhus and plunder the Granary. The one that possess Cnaiur is a DIFFERENT AJOKLI, made over along with the remainder of the Outside by Resumption. His rage is Cnaiur's rage, Esmenet's rage...the homicidal outrage of the victim, the desperate search for the one accountable, doomed forever to failure.