First of all I know Cowl's identity is a well worn question, but after looking around the forum I didn't see this seemingly obvious idea put forward: Odin is Cowl.

So who is cowl and what do we know about him? He's a dude named for his attire, a cowl. His magic "feels" dark and powerful but mostly mortal. All the direct actions we've seen him take are doing one of three things:
1. Killing people or trying to kill people.
2. Stealing power and knowledge.
3. Manipulating the politics of various nations.

Who is Odin and what do we know about him? He's a dude nicknamed after his attire, a cowl (One of Odin's most famous names is Grimnir, from the Norse story Grimnismal. Grimnir means "hooded one". Dude's nickname is literally Cowl). In the dresdenverse he used to be a God, but became killable to stay involved in the mortal world (WoJ), so presumably his magic is "mostly mortal". All the things we've seen Odin do (and the things he does on 99% of the stories about him) are one of three things:
1. Killing people or trying to kill people (and titans).
2. Stealing power and knowledge (in the sagas Odin has like 5 separate stories about stealing power and knowledge, and he kills people in most of them. In one, mead flies out of his butt, at least according to Niel Gaiman.
3. Manipulating the politics of various nations.

Jim has said that some of the characters we think are nice are gonna wind up as traitors. That was pre-BG, so he could have meant Justine, but I'm always asking myself why one of the most sinister explicitly "black wizard" figures in mythology is portrayed as a really nice helpful dude in dresden files. Odin will seduce you then murder you because he wants to steal your dad's stuff. Dude is literally a necromancer. He isn't a nice guy. Also starwars fan Jim chose to use "Vader" in Odin's public persona.

A couple times Jim has said that giving readers clues is tricky, because sometimes he thinks things are super obvious, but reads miss them. I wonder if having a black wizard named "hooded one" out of mythology and having him disguise himself as a black wizard named "hood" is one of those.

"But wait," I hear you say, "Odin claims that he and Uriel have lunch once a year, and  One Eye's use of the Mr. Sunshine nickname supports the idea. Odin could be lying, but I'd he's telling the truth it implies Uriel would associate with an evil power!" Mab. Uriel worked with Mab. If you believe Bob, the archangels have even worked with Lucifer post-fall on Job. I admit that his association with Uriel is a big flaw, but it's not inconceivable to me that either the angels are more old testament than dresden realizes, or Dresden drawing a line between the Black Council and Nemesis is in error, the way Rashid's take in TC was.

Mab has demonstrated her dubious regard for the accords several times, and she literally wrote into them that there is no spirit of the accords, only the letter. In basically every book she's had a major appearance in, she's come very close to violating the accords herself. She doesn't care about the moral principle of keeping clear of grey areas, she uses those grey areas to her advantage. Keep in mind that she's helped nations violate each other's territory, tried to kill freeholding lords, specifically ordered her knight into situations she knew were dancing on the bleeding edge of the law. Then Lara Raith the queen of tretchery comes up like "hey mab, do you mind if I cash in my favors in an extremely specific way that gives me access to the literal only person in your court who is both capable of violating winter law, and probably won't tell you if he does?" You think mab didn't read the subtext there? Mab is not an ethical person, she's a person bound by ironclad rules she does her best to violate.

I think a lot of the issue with the knight's power is that neither of the current knights are really trying to use their power to the fullest. Harry hasn't really put the mantle through its paces that we've seen. I'll divide the mantle up into three "areas," mental, physical, and magical, and look at what Harry has done with each.

Mental:
Harry sees the winter mantle's mental influence as entirely negative, and works only to suppress it. This makes sense, given how afraid of his own darker nature he is, and the repeated theme of "Harry is often dense." Even in CD and BG when he lets it run things in battle, he's basically just leaning on the basic, hindbrain inclinations, not using it. My theory is that the only time we ever see the mantle fully in control is when he's trying to kill Rudy in BG. Harry thinks of his mantle as just animal savagery, but Mab IS winter, and she's mostly logic, not animal aggression. Pure winter is cold primal logic unbound by remorse or ethics. It's ruthless logic, not just ruthless. I'd bet Mab was leaning on her mantle quite a bit while running all her glamours during BG. We know from Molly that an extremely talented and well trained human can do like half a dozen purely phantasmal illusions at one time. Mab is doing thousands of them, AND making them physical. That's not just a matter of having more power or more experience, that straight up requires way more processing power than a bipedal hominid has. My bet is that her mantle (an the other winter mantles) can help her with cold logic, aka processing power for magic and whatnot. We don't actually know, because Harry hasn't tried to explore the mental side of his power, only bottle it up, a choice I consider to be a straight up mistake, even if it is in character. (Un?)Fortunately, Molly doesn't seem to be making the same mistake.

Physical:
The winter mantle makes you stronger, faster, and more enduring. It cancels out pain, makes you key up for a fight faster, and improves recovery time. It makes Harry about as strong, fast, and tough as a person can be. Except no, it makes him WAY stronger and faster, it has several times, and Harry doesn't seem smart enough to explore this. The dude has ran faster than a vampire and taken a hit from an Ik strong enough to flatten cars (changes). He's lifted more than a ton and jumped forty or fifty feet (both in cold days). He casually jumped off a three story castle, and went hand to hand with a titan. The mantle obviously provides WAY more than "merely" peak human strength. Harry just hasn't put together yet that what it does in the gym and what it does in actual combat are very different.

Magical:
Harry is just using winter as a battery. Hellfire? Used it for things as abstract as imagining it helping him in mental combat. Soulfire? Uses it for communication, construction, destruction, and more. Winter? Duurrrr... Winter BAD. Emergency battery only! What a dummy. Dude even notes several times that the mantle has a seriously obvious "pack hunter mode" that orients to the people around him, but it never occurs to him to put that through its paces until Ethniu helpfully sets up an opportunity for him. I get that Harry is still growing, and a theme of the later books is him being more prepared, but seriously dude, take mental inventory. The mantle is there whether you like it or not, put it through its paces. Thomas and Mab both warn him about it in their own ways.

Overall I think we've just only seen three knights wasting the potential of the mantles. Slate was an idiot, Harry has a martyr complex, and Fix has only really had any competition for the last few years. Harry's lack of diligence seems pretty out of character, but I get that he's kinda been reeling for a few years. Still, having a repeat of the Hellfire story seems lazy. Harry trust(ed) his ability to know when to stop. A freaking Archangel trusted his ability to know when to stop. Dude absolutely should have done his testing by now.

Honestly I suspect the Archive's function as the mortal-side conductor of the oblivion war was something Jim came up with after Death Masks, not something he had in mind from the beginning. He's said his initial genesis for the archive was just wanting to write a creepy little girl character. It's sort of hard to justify a being as vitally important but (mostly) mortal as the archive ever hazarding herself in field work. How do you logically go from "My job:  use intellectus to keep track of all human knowledge to watch for cthulu cults" to "My task: get involved with random supernatural disputes all over the world."

After a readthrough or two, either I'm missing something or the White Council is kind of a joke. If there is any in-setting reason why they've survived this long, it must be because they have benefactors helping them behind the scenes. I'm more of the Opinion that Jim just didn't really think things through, although I don't really blame him. There's that old thing about "write what you know". If you aren't a lawyer, don't try to write a detailed court procedure. If you don't have martial arts experience, don't try to write a detailed blow-by-blow of a clinch for a grapple, etc. Obviously good authors get around this by reading the writings of subject experts or directly consulting them, or they use abstraction to avoid the issue entirely. Robert Jordan wasn't an expert swordsman, but he has some of the best sword fighting sequences in fiction because he uses evocative but largely unexplained sword-fighting forms to describe actions. "Arc of the Moon countered Parting the Silk, which flashed into Heron in the Weeds," etc. Jim's problem comes from the fact that he isn't a .01%er, and there's (supposedly) no 300 year old illuminati guys to talk to in real life so he didn't think through how a group of hyper-rich information brokers would actually go about business.

Jim calls attention to the idea of how conservative long-lived organizations would work, but what exposition says and what the books actually show are very different. The Black Court is a perfect example of about how failure to adapt is absolutely fatal to long-lived beings. The black court have all the tools to be discrete manipulators on par with the white court, but they didn't use those tools wisely, so they were almost wiped out. They have infinite time, infinite money, can control the minds of mortals, have immense leverage when dealing with supernatural beings, and are massively dangerous if ever confronted directly, a lot like wizards actually. Predictably, the only ones that survived the stokerclipse were the ones who used those advantages, kept their head down, and mostly kept out of direct confrontations. Just like wizards. The problem is that how the wizards are described (how the mechanics of the setting established they SHOULD work) and how they act in the books are radically different.

They have wizards answering the phones? THEY HAVE WIZARDS ANSWERING THE PHONES??? It's an organization of 200 year old millionaires lead by a group of 300 year old billionaires, and they don't hire personal staff? Rich people don't do anything themselves. Once you get above a certain income bracket, you start hiring assistants, both because it's convenient, and because your time is way too valuable to be spent doing your own taxes, answering your business phone, or wiping your own butt. Yet you have wizards doing drudge work administrative tasks? Personally doing ground-level assessments of warlocks? Wizards aren't *just* hyper-rich elites, they're technical specialists whose talents require centuries of dedicated full-time practice to develop. It would absolutely be worth spending 100 grand a year or whatever to hire clued-in staff members to take care of all the little details. Peabody being a dedicated beurocromancer for the senior council doesn't bother me. Wizard Macfee(?) answering phones in Changes does. Morgan, head ass-kicker and #1 field guy of the council personally following around wardens for YEARS does. Captain Luccio, commander of the wardens, sitting in front of a phone on desk-duty in the middle of a crisis point during a war does. The White Council should have dozens of hundreds of staff members for every actual wizard, including a ton of mercenaries, allied spirits, and personal retainers to help in the war, yet when we see crisis points it's never a wizard and all their assets, it's two wardens and three noobies responding to a council-ending crisis, or six dudes on a boat coming to throw down with two of the most dangerous people alive. You'd think there would be dozens of wizards who made their fortune by building businesses based around providing confidential, clued in help for other council members, but the only person we ever see doing that is One-Eye.

By contrast, Harry is what, late thirties, early forties by the later books? And he has like a dozen people he can call on for help in a crisis, or even everyday tasks. Dude's got half a dozen warriors on hand, a pack of werewolves, several fae allies, multiple vampires, and a gang of favors he can call in. I get that he's a protagonist, punching above his age and means, but if he can get that in like 15 years as an active wizard, why don't the senior wizards have PILES of resources to call on? Even in emergency "the red court is actively kicking our asses" situations, why on earth wouldn't Luccio have hired some Einherjaren or whatever for the Darkhallow? Why are senior council members personally risking their lives to bring in a prisoner when they could whistle up a gang of spirits to go poke that beehive first? Personnel restrictions can be explained by the war, but not the bizarre risks taken by council members, or the sheer bizarre internal structure of the council. Why are wizards answering the phones? WHY ARE WIZARDS ANSWERING THE PHONES? I know this is an odd thing to fixate on, but imagine Elon Musk or Bill Gates or whatever sitting at a secretary's desk going down a call list verbally giving out an employee newsletter. Then remember that maintaining your talent as a wizard is a full time job on top of whatever other responsibilities you have. So Elon Musk is running his companies, personally doing secretarial work, and holding down a full time job as an engineering supervisor. What?

The mechanics of the setting have absolutely hammered home the idea that an organization that works as inefficiently as the council does should have been destroyed decades ago. For the last couple decades they've had Harry there personally pulling their bacon out of the fire, but what about the 100 years before that? It just really seems like the council should be gone by now. Lara Raith even calls them out for this in Turn Coat, but the text acknowledges the idea without actually implementing it. I really hope I'm just missing something, because it seems like a pretty big error.

There is another male character/characters associated with TBC that have a past-present-future correlation. *bob voice* there's more than three dimensions Harry, time counts too. "Walking Before" could easily equate to the future, Between (I know it's Beside, Jim is dumb and wrong, He Who Walks Between sounds way cooler) the present, and Behind the past.

The Great Lakes were only formed by glaciation 14,000 years ago, suggesting that Demonreach the island would not have physically existed at this point, perhaps Merlin decided this would be the new Supermax

I can't find the WoJ for it, but somewhere Jim said that The Gatekeeper wasn't the one who caused Daemonreach's limp, that was the glacier that carved out the lake, implying that Daemonreach is older than the lake.

I agree that it likely exists in multiple points of spacetime, given it was made that way (five at least), and also due to the power that five has magically speaking in the series.

I am not sure I agree it actually moves around - although that would make logical sense - I am not sure it's actually the case in the series. Simply put, from what we have seen of magic, it's incredibly hard to do something like physically move an island (borderline impossible) for a human. So unless a Dragon (capital D - like Ferrovax) or something of that order or above got involved, it would not be possible. Even so, it seems like they still use regular physics to aid them rather than simply being like a Minecraft editor. Given Jim said something about Dragons being told to "divert rivers" and "split continents". 

...

Still though, I like the idea of a moving island. Would certainly have been more convenient for the Original Merlin, and make more sense why he is connected to a random island in America. That said, still doesn't explain how or why it moved there from wherever it was.

I probably didn't explain it very well, but my idea was that it had 5 static locations, that it could be "expressed" through one at a time (or possibly all 5 at once, if you were trying to bind everything on a planet at once, but that's a BAT crack theory), thus the question about different disappearing islands located throughout the world. Sort of 5 different quantum superposition states, and the warden can affect the probability that the island's matter will be expressed in each location. Need to bind something in North America? *button push* Demonreach. Baddies acting up in Europe? *push* Avalon. Titans crawling out of the Mediterranean? *push* Circe's Island. The island isn't physically up and flying or floating to another location, it's just existing in 5 locations at the same time, and is accessible from those locations at the Warden's behest. As far as power requirements go, I'm sure all 5 locations could be on leyline nexuses, and there's a big ole dark energy battery in the Well.

I do recall, I think in SG, that Harry remarked he wasn't really sure hewas still on the island when descending deep enough down - finding the depth implausible.

It could be like Maeve and Aurora's courts in SK, where the physical location of the entrance is at a static point in the real world, but the space that entrance leads to is either in the nevernever or "between", since Harry always comments on how things feel different in the Nevernever when he goes through a portal, and never says that about their courts. But he DOES suggest that the physical space of the court doesn't make sense in the location it's supposedly occupying in the real world (giant ballroom in a commuter tunnel, tropical forest on top of a skyscraper). The Well could be another "between" space, with entrances in the mortal world. Perhaps 5 entrances on 5 different islands?