"4" beings who maintain the balance of the abyss, but who's the fourth?(and other character discussions too)

So, ive been looking at the knowledge tab, and I can't find the 4th being anywhere, already on chapter 12 so it may be revealed by then, but I have a feeling it's goyen/future kliff(not confirmed but cmon bruh its obviously him)

on the topic of goyen, what version of kliff do you think is he? From what he said, it feels like hes either the amalgamation of ALL kliffs (so if there is a multiverse, kliffs who failed succeeded and everything in between)

But i like to think that he's a future kliff who failed to save everyone, but he was able to bring balance to the abyss(sorta like ragna crimson)

if it isn't goyen, maybe it's hexe marie? i know shes evil, but it's also heavily implied that she's either white crow's twin, or "dark self"