What have I missed.

[vincentric]

She’s not a properly mortal practitioner like a Wizard, she’s a Changeling. You are inferring that one set of rules apply to her when it isn’t clear that is the case. We do not have enough information to ascertain whether the same rules apply as regards mortal practitioners, whether she was taught a way to hide this or whatever by Nameless/Cowl. We do however have the facts set our above as regards her and Kumori’s time-line and that of Nameless and Cowl.

She spent decades making sure she was overlooked so as not to get on Maeves radar, so of course she was hiding from everyone.

I'm afraid I've forgotten all the facts about Nameless. Could you please give the book or WoJ quotes outside of those in The Law?

[Conspiracy Theorist]

There aren’t any, unless you count Even Hand where Marcone is reading letters from his unnamed lawyer about the Accords.  This is from the collection Dark and Stormy Knights and Even Hand did not feature a dark knight, until at least the reveal in Battle Ground. The Law established that Nameless was employed by Marcone at this point in the time-line.

there is a possible mention in Summer Knight page 203

‘‘There,’ she said, once I’d been seated. ‘Not so untamable as he claimed.’ I felt my jaw get a little tighter as Billy took a seat beside me. A trio of brightly colored lights zipped in, bearing a silver tray holding a crystalline ewer of water and two glasses. ‘As who said?’ Maeve waved a hand airily. ‘No matter.’”

Maeve refuses to name her informant. Slate walks in just after this and has no idea who Harry is. At this point Nameless would have been a prominent part of Maeves Court, his presence creating the discord that existed there with Lloyd Slate and the Changelings and exacerbating Maeves own misconduct. No -one in Maeves Court would have bothered to keep an eye on Harry….unless they were also Cowl.

Of course this could be red herring as Harry actually asks a timeley and pertinent question.

Nameless was obviously keeping a low profile during Summer Knight, he didn’t want to appear on Harry’s radar. Harry had no prior interaction with Nameless in his entire PI career, which seems strange as he is a very successful criminal defence lawyer, unless Nameless wanted it that way. Nameless knew who Harry was.

I also suspect he was the anonymous motorist who rear ended Harry coming away from the WC execution in Proven Guilty, the WC coming to town when he is organising the attack on Arctis Tor using the way through Pell’s Theatre mean’t he needed to keep an eye on them and liase with his mole Peabody. His temper got the better of him (Harry denied him full godhood the year before in Dead Beat) as it did in Fugitive after his scheme with the Titan was ended also by Harry.in Fugitive Cowl is seen as uncharistically petty and vengeful he isn’t running some great scheme as seen on his previous appearances. Harry is very good at annoying people, even Uriel who is several grades up from a Saint.

Basically Jim can point to Nameless always being there, in the background, in every case file behind the scenes training Sorcerors, giving out HexenWulf Belts, and Athames, setting the Courts in Dispute and prolonging the Red Court war, manipulating the Denarians, raising up the Fomor. and as I suspect we are going to get the Cowl reveal in Next Book as Harry slowly over the year putting the pieces together which is why we got The Law when we did.

[The_Sibelis]

Basically Jim can point to Nameless always being there, in the background, in every case file

indeed? The regardless of if he is or isn't cowl, did or didn't have a hand in those things.. I gotta say it just doesn't have any oomph of reveal to me without a deeper connection of whom nameless really is?  I mean, if the supervillain reveals himself and says,"it was ME all along Harry. I did it." And Harry's best reply is,"who the F$&+ are you?" Then he's delegated to... I'm not sure the word, I wanna say mcguffin, but cross that with the fall guy in any Scooby Doo episode.(he'd be the meta version of Vitto!) And that just doesn't seem enough without anything else on nameless, it'd be a cheap sell without his backstory, which probably exists.. he's likely one of the main players Jim talked about,"we still haven't met all of them yet." I find it particularly likely he's tied to any bureaucratic threads, possibly taking on the role id presumed "commissioner fairweather" played in stifling Murphy. The name, reveals it was always meant to be a fae subplot to me.
Point being, if you could give me some good ideas along the lines of WHY is nameless. His motives and what not I'd find this idea far more interesting a read. By and large I think motives give good broad strokes to base theory on.

[g33k]

... No-one in Maeves Court would have bothered to keep an eye on Harry….unless they were also Cowl ...

Margaret LeFey's son?
The Leanansidhe's faerie-godson (for a couple of decades at this point)?
Mab's Emissary in a conflict with Summer?
Someone high-enough in Mab's estimation -- having been the object of Mab's attention -- to be offered the job of Summer Knight?
Likely Starborn wizard?

No... obviously, Maeve and her court have no possible interest in Harry Dresden.   
 

[Conspiracy Theorist]

Oh nice point, a mortal who isn’t interacting with the Fae until Mab forces him to be her emissary in Summer Knight is a point of constant Fae gossip years before that event.

Lea only came back into his life in Grave Peril the year before and she is definitely not a ‘he’. I doubt she makes her bargains public and Harry has kept silent about her until Grave Peril. She was not going to make her being duped by Harry more public unless forced to by say Mab under Winter Law, (which appears to have occurred) or someone who gave her the Athame via Nemesis. We are talking the deathcap incident, that Harry would rather die than be tamed, and beat Lea. This point only suggests Cowl is Nameless as only he would be in a position to follow up on the gift when it started taking effect. It must have given Cowl a warm little glow that Mab wasn’t getting her choice of Winter Knight, because Harry is untameable. Mab didn’t tell Maeve this (definitely not a “he” either) that leaves a male third party with access to Maeve and Lea in Winter and with control over Lea. Now who could that be?

Even the Erl King didn’t realise Harry was the son of Margaret Le Fay, that reveal didn’t come until Battle Ground I believe. Kringle knew (Vadderung is keeping tabs on all Starborn I bet) and Mab knew via Lea. It is likely this only became better known among the Fae after he was appointed Emissary and then Winter Knight. Then the gossip began.

At this time Chicago was already a base for the Swartalves, the White Court, Red Court and Nameless  was planning for Maeve to move her Court to Chicago, forcing a similar move by Aurora (whose Knight was already based in Chicacago)

That you confused Winter and Summer Knight is probably just a slip, I know exactly what you meant.

[g33k]

Oh nice point, a mortal who isn’t interacting with the Fae until Mab forces him to be her emissary in Summer Knight is a point of constant Fae gossip years before that event.

We don't know what the fae gossip about.
But Maggie Sr. was certainly one of their topics, and her son may have been of some interest (mortals' children, historically, are hugely interesting to the fey).

Lea only came back into his life in Grave Peril the year before

Lea made a bargain with Harry when he was 16.  Did she leave him alone thereafter??!?
I don't think so.
The wiki says:

In Grave Peril, the Leanansidhe has spent many years attempting to get Harry Dresden to honor his bargain and become hers /quote]
_{- https://dresdenfiles.fandom.com/wiki/The_Leanansidhe?so=search#Grave_Peril}

If she was throwing lures & tricks & pressures his way, it's entirely-possible a bunch of faeries knew about it, particularly those in Maeve's court:  Mab's handmaiden is only slightly-less-interesting to Maeve than Mab herself!

But we also know that she was active with regards to Harry -- busy "Faerie-Godmothering" -- for a long time.  Protecting him, without his notice.

... Lea ... is definitely not a ‘he’ ... Mab ... (definitely not a “he” either) ...

Definitely!

But I assert there's plenty of "he" individuals who could have offered Maeve info on Harry (the Redcap springs to mind, but a bunch of Maeve's bully-boy sidhe are "he's").

... Even the Erl King didn’t realise Harry was the son of Margaret Le Fay, that reveal didn’t come until Battle Ground I believe ...

Pretty sure you are mistaken, there:  I'm away from home, can't check the scene, but in Changes when Susan & Harry were in his court, the Erlking referenced Margaret LeFey.

And Goodman Grey knew...  Why the !?&%$ would a random deep-cover mercenary have track of the long-lost son of a 3-decades-dead wizard??!?  If GG knew, I have to think it was well-known among the fey.

[Conspiracy Theorist]

There is nothing as boring as talking about other peoples children, so no Harry was not gossip worthy.

Harry let Lea  back in in Grave Peril. He studiously avoided her otherwise.

Lea is not going to let anyone know she was forced to re-negotiate a bargain with a mortal untameable would suggest they know despite her pride.

Which “he”? Not Lloyd Slate who as Winter Knight was supposed to be the go to guy on mortal matters. Who else had connection with the mortal world but was in a position to advise Maeve. Some new character we have never heard of still?

[The_Sibelis]

Eh, they were gossiping about who Margret had been "sporting" with and that he apparently "scored a goal" much better than lord Raith.