Fun things from Mizuki's OpRec that I just watched.
Gladiia can move quickly enough to essentially teleport and its clear that her boast to Irene's mentor about "your walls being like paper to me" was no idle threat as she casually splits a steel door in twain with her Lance. Which is sharp enough that the cut is clean. Abyssal Hunters don't fuck around.
"Yes Gladiia, I hid Mizuki because otherwise you'd have killed him before I has the time to utter a single word"
Kal'tsit knows her girlfriend too well.
Kaltsis, much like Ulpian wants the Hunters to consider talking to those of the Seaborn that can talk back. Gladiia says she will consider it.
I can't say I believe her. She might have had a change of heart after talking to Ulpian is she might just be saying it because Mizuki is currently hidden beyond her Lance-reach.
It's clear that Mizuki is a Seaborn but one with intelligence and thoughts of its own. Rather like a Herald is it not?
And Rhodes Island is keeping him with them instead of killing him in an attempt to guide his growth into a form of Seaborn that would be open to cooperation.
(I know IS3 goes more into his nature, I'm ignoring it since I don't want to spoil myself)
1. Swearing is fine as long as it's not in English.
2. Dossoles seems to have problems with child trafficking.