We may have seen x-iel or at least his host, the Fallen can keep hidden especially well, Harry may have fought him and not even realised he was facing a Denarian, Cowl for example is a likely candidate, he never pressed Cowl hard enough for him to draw on Hellfire in their battles. Cowl however knew Harry possessed Bob, who had the Word, if Justin was a previous host x-iel would know this. It always bothered me that Cowl knew about Bob when only Justin, Elaine and Harry knew this, so Cowl must have found out from Elaine, unless there was another being present all the time. Everyone goes with the Elaine-Kumori theory, but if she was bound to Summer at the time of Grave Peril, it’s unlikely given how we have subsequently seen how Winter binds.

It's possible, but not the only way to explain Cowl knowing Justin had Bob and surmising Harry would have taken the skull after defeating Justin.

We have little to no indication in text how much information Justin was sharing with other Circle conspirators without Harry or Elaine's awareness. It could be something as simple as Cowl knew because he helped Justin purloin the valuable assistant spirit out of Kemmler's lab while convincing the Council it had been destroyed.  That's a particularly credible alternative if Cowl is Simon - everyone pretty much would have believed Bob was destroyed on his report as Senior Councilor and head of the brute squad.

Of course, Cowl could be both Simon AND hosting one of the Denarians everybody thought was still in a Church vault somewhere. A coin would certainly be helpful in faking one's death.

Interesting ... I'm not sure if that's the one Jim Sr mentioned his son working on where the magic system causes slow sanity corruption and the magical enforcers are partnered with a mundane who's supposed to put them down when they eventually go dark, or it's something else.

Merlin might have travelled more widely in the Americas than just the Great Lakes area to set up the prison on the island, and European legends about him just didn't record it. He was clearly a lot more influential and around a lot longer in the DV than just the "advisor to King Arthur" that the real world legends have him as.

Or, it might have familiarity with the runes through a third party. Vadderung was supposedly a mentor to Merlin, and I'd be 0% surprised if he'd tangled with them at some point. And wasn't there supposed to be some sort of connection between the island's runic alphabet and the Hecatean Hags from the comic? Maybe it had dealings and was frustrated to be countered by something similar to their alphabet.

Also, do we know that only the British Prisoner is the only being in contemplation mode?

IIRC there was some Harry narration when he confined Thomas that there was only one other prisoner under the contemplation protocol.

It wasn't explicitly stated to be the British guy, but it's on the same tier of really strong implications as the blackstaff being MW's walking stick.

I suspect when Harry finds out that Molly was prepared to sleep with Carlos, despite what ended up happening, Harry isn't exactly going to be cool with it. Particularly inner Harry.

I'm not sure he's going to find out at all. But he wanted her to stop pining after him, so her finding an alternative attachment with an age-appropriate good (at the time, anyway) person seems like about the best case scenario. I'd think he'd be more sorry for her tragic predicament.

Namshiel appears to have thrown in his lot with Marcone, less than happy with Nick, we know that there are also a hidden faction working with the Black Council that worries Nick, Lasciel is suddenly interested in her child with Harry and willing to make an alliance but not out of obeisance to Nick, out of necessity.

Nick’s power over the Denarians is at its weakest in 2,000 years, so we may see more a mere two books after Next Book. We may find out who was the Denarian on the Black Council (I call Tessa, it will hurt Nick the most, and he had little control over her, I think Nick kept Namshiel on a very tight reign, his speech was archaic suggesting Nick put him in cold storage when he didn’t need him for big magic)

Mostly agreed. Namshiel seems to have been more aligned with Tessa than Nic, though. And his archaic speech was probably more a function of not caring enough about human affairs to keep up to date - he kept his last host tightly enslaved and mostly just focused on his magical experiments for quite a while up until Michael killed that host.

Realizing there is a Black Council mole among the Denarians and suspecting 1) it's Tessa 2) she's setting him up as her scapegoat ... that would make a real good motivation to strike out on his own. Maybe coming to more of a partnership relationship with Marcone is a product of realizing he can't afford to be the magic nerd anymore, and needs a power base independent of being part of anyone else' cabal.

Alfred is an ally not a power and harry’s Intellectus and his ability to manipulate the structure of the island are the only powers demonstrated by Harry to date as Warden. Maeve at one point neutralised Alfred with sufficient stacked Fae power, there is therefore at least one recorded instance that Harry could not rely upon Alfred as an ally on the Island.

Did she really neutralize Alfred, or was he just sandbagging to play for time?

Mab thanked him for his restraint afterward. Suggests he could have done more but chose not to.