Pages 21-22 of
Carciphona: Volume 4 are up!
I don't believe that demon infusion is irreversible despite what Kasga said in the new pages.
Really, what ending would that leave us with? I came to the conclusion a while ago that by the end of
Carciphona, Blackbird will be either:

free of the demon spirits that she is likely possessed by
or

dead
Or Shilin could just leave her hanging. I've seen it before. But I doubt it.
I don't know.
And...where might that leave Veloce? (if demon infusion is irreversible)
If Blackbird died, that would kinda suck.
If Veloce died, that would really suck.
If Veloce
and Blackbird died,
Carciphona wouldn't be a story anymore. By definition, it would be a
tragedy.
Carciphona has a thick and intricate but delicate plot. There is an official main cast of only four: Veloce, Blackbird, Keri, and Weirin. If something happened to any of them, it would mess up the whole story. The protagonist (Veloce) and probably the antagonist (Blackbird) are both demon-bound. If it is actually true that demon infusion is irreversible, the plot is static (unchanging) and pretty much doomed to a bleak, indifferent, and unexciting ending.
Simply put (for people like ~
LordofStupidity), the story would just stay the same and have a boring ending.
On a brighter note:
[link]Vocruen left long ago saying he could not let Veloce come with him because "[he] will put [her] in danger." That always seemed a bit shady to me...Now here Blackbird is saying that Vocruen was "as treacherous as [she] is." AND now here Vocruen is summoning what looks like demon spirits with a dark and shady expression on his face. You can go so far as to say evil. If you don't want to, you have to at least admit it's questionable.
Vocruen was with Veloce when she was eight, and left when she was thirteen (Veloce mentioned in Volume 2 that it was four years ago, and she's seventeen now). So he was with her for at least five years. Yet Blackbird says she has talked to Veloce more in the past few days than Vocruen has his whole life, and Veloce doesn't deny it. That's very little conversation on Vocruen's part for five years...you could go so far as to call it neglect. Hmm...I wonder what he was so busy with...?
That's the past, though. In present-day
Carciphona, Vocruen is dead. Shilin even mentioned in a comment that he's as dead as it gets, and she doesn't lie to her readers. Veloce doesn't believe it.
Also...Blackbird talks down to Keri, Meron, and now Vocruen as if they're pretty much useless to Veloce...
but what makes her think she's so valuable to Veloce?! 
She's practically possessive of her.
Oh, and I hate to burst all of your bubbles, but a few pages back, that was not an uppercut. It was a slap. Veloce's hand was open.

Veloce's dismissiveness was clearly because -- as we could tell from the very beginning of
Carciphona -- she wants to be left alone, and because Blackbird hurt her feelings. Up to now she's really just tired, maybe even exhausted, of Blackbird.
Maybe Blackbird will leave her alone for a little while to make room for the rest of the story to progress, and let us find out more about Vocruen.
Maybe she'll listen to Veloce and stop being so selfish.
Yeah no probably not 

This has been StrongButGentle