Miura's comment for this issue: "I encountered Kotori Yoshio in a coffee shop."
You don't seem to take into account the fact Femto was incarnated into the corporeal world by taking over the boy's corporeal body. The boy was not a purely spiritual being; he had a body of flesh. The evil that had tainted him in the womb just gave him unique powers and placed him firmly in the Interstice.
Yes, Serpico has been somewhat aimless for a while, long before that in fact. His relevance has diminished as Farnese grew stronger and more independent. I'm sure he'll find his own way eventually though, and Elfhelm seems like the perfect place for that.
On a side note, there is no "mermaid arc". To see all episodes, chapters and arcs of the series, you can consult this handy list: http://skullknight.net/manga/.
Don't hesitate to direct that person to this thread, most of which has me lengthily arguing against that idea. 
Excuse me, i meant to say i think the boy is Guts and casca's child but my understanding of that baby is he was spirtually transfigured or maimed before birth. And never got a chance at life(incoming graphic description) and I'm not even clear if casca has him as a still birth or if the panel in which it appears to be that it isn't his fetus persay but he's already been turned into his ethreal ghost like existence. I do seem to recall him passing on in a sense before he reappears in his more memorable(i guess really for me) form that he would protect Guts in.
I suppose it's true he must have had flesh if he was eaten but i'm not sure what the beherit apostle could "eat" so to speak.
Point being though he is born again into human flesh, through that whole second eclipse and he would be in some sentiment the opposite story of griffith.
Or the other half to the whole.
Griffith was a man, who died to become a god(well god hand), and that being was born again in this world.
The boy(moonlight boy) was more of a spirtual being made into flesh. In the sense that the existence he came from was one that was on that plane. Rather than going from this world/to the spirtualto this world again, he came from the spirtual to this world to lead the life he never had the chance to live.
Even if he was technically corporeal(or of the flesh?) before this rebirth(if it is him) he seems like he represents the reverse or opposite of the way the rest of the way things have gone with everything else concerning "fate"
If you've ever read/seen dragonball/z you'll know of the story of kami and how he split himself into two halves from his whole, in order to become pure good, or the mystics and the skeksi's in dark crystal. It seems like a part of the birth that was designed to bring fempto into the corporeal world created the opposite effect for griffith's(i guess a dark kami) and left an innocent half floating around.
he seems like the one force suggesting hope of postive recovery, in the spirtual. Of course it could all turn out bad, and schierke seems to understand a whole world of postive spirtuality, and we haven't been to elf island which seems to hold the possibility for some healing for casca.
Also apologies on refering to it as "the mermaid arc" i wanted to refer to the parts of them fighting the sea god, that focuses on Isidro meeting the girl( can't for the life of me remember her name right now apologies) who ends up becoming a mermaid(not sure if i'm remembering correctly that they even call them mermaids.) To me he really took a center stage there. I feel serpico has a lot to give, with the brilliance of the silat/rakshas fight it has me looking to see more of what can be done with him and what he can do in fights based off those magnificent fight scenes with Guts.
