They sent a small army to achieve a specific purpose. A few details. All the dead that we know about died when hellfire was thrown at Arctis Tor and belonged to the defenders. No bones of any of the attackers is seen, and the only living beings at Arctis Tor that are revealed are the fetches. The portcullis is blown apart, yet the tower is intact. There is no indication that anything other than the fight in the courtyard occurred. And if Mab is so frightened of an attack occurring at Arctis Tor again why is it so lightly defended. One Wizard, one White vampire and two mortal females knock on the door and make their way to the Well Spring with the aid of an automatic door.
Hmm the text does not support this - unfortunately I have the audiobooks so I can’t copy paste the exact text, but if you re-read the scene where Harry & Co. first make it out to Arctis Tor (Chapter 36), there are subtle hints that other things were at play here. For example, when Harry is examining the bones at the entrance to the city (50 yards from walls), he notices that some bones were “pulverized to dust in some places” & “warped like melted wax in others”, combined with the fact that he notices acid had pitted the walls of Arctis Tor & smells hellfire in some of the other larger craters on the same wall tells me that there were forces in addition to Hell playing a part in the assault.
By the time Harry gets to the main gate, he is wading “shin deep through bones. Whoever they had been, thousands of their kind had perished here... Where the gate arched beneath the fortress walls, there were still more bones, waist deep on me”. In chapter 37, as Harry goes deeper into Arctis Tor beyond the gateway he notes that there are so many bones that he can longer walk through them, he has to walk atop them.
Harry explicitly notes that the courtyard is littered with the bones of Mab’s defenders. “Echoes bounced back & forth in the courtyard, somehow carrying a tone of disapproval & menace with them. Bones spilled out in a wave from the gate, rapidly tapering off after a few yards. Beyond that, were only scattered groupings of bones.” Harry notes these are trolls, 13 of Mab’s personal guard. He then notes that the “remains of perhaps a thousand creatures lay scattered about”, mentioning that even in GP when he let loose, he was only able to fry a bunch of Ramps/people, nothing on this scale. He goes on to note while examining the remains in the courtyard that “the littler ones were goblins, foot soldiers.... these trolls were her [Mab’s] personal guard, covering her retreat to the tower maybe. Some of them got taken down along the way, others made a stand at the tower’s base, died there.”
This shows that the either the fortress was not lightly defended or the army attacking was not small, since Harry is unable to identify the bones this far in (except the courtyard). There was clearly a substantial battle, & while most of Winter’s troops were at the Summer border, there were clearly thousands of Winter defenders who gave their lives during the assault on Arctis Tor.
The presence of thousands of bones in the courtyard - those of goblins & trolls decimated by hellfire shows that the attack made it fairly deep into the fortress - but the attackers were unable to breach the spire for some reason (where Molly is held).
The entire reading of Harry’s thoughts as he makes it to the spire does not read to me like Mab masterfully sacrificed thousands of her subjects just to see who would come to attack her fortress.
I'm not suggesting any time traveling portals, I am simply saying that Mab does something similar to what we know that Maeve did. If Maeve can slow the rate of time for the forces returning to the border to give Summer the time to carry out attacks against the Reds then one could presume that Mab could stretch time to slow any forces attacking her stronghold. And one year after the incursion the Reds are still moving in Faerie unless we assume that Summer sends her troops to the mortal realm to strike at the Reds.
This is an interesting idea & one I hadn’t thought of. So you’re saying that Mab figures out that someone from Summer is involved in the assault on Arctis Tor, so she sends all her troops to the Summer border & then slows down time at Arctis Tor for nearly a year (while only a few days pass at AT) so she can deal with the assault?
Definitely a cool theory, although I’m not so sure that Lily was involved in the initial BC assault - there seems little need for it. And Mab doing this would definitely complicate the complex timeline of events considerably.
Whatever happened at Arctis Tor happened at the heart of Winter. It takes all the Summer Lady's strength to hold the portal open. If the portal is the path the assault on Arctis Tor occurs through, then it seems reasonable to assume that someone of at least her power level was required to do the same for the forces involved in the assault. If Mab knows what happened she may not know who aided the BC to make it happen. And the list of suspects who could aid them is short. And Summer is the only true credible threat. Summer is the only force that could attack from the border of Winter and hope to win through.
Now tally the forces. Lea is down, the Winter knight's power is not in play. And Mab has to at least be suspicious that Lea has compromised others in the time she has had to spread the contagion.(which we know to be the case) And may fear that Aurora did something similar to Summer. She has to play defense, hunker down and ride it out until the Courts are back at parity and she has the freedom and forces to move against her enemies. And picture this against the background of what we know Maeve wasn't doing, which was keeping the army fed with troops.
It still seems easier for Maeve to have been the inside help the BC needed to open a direct portal, although even this is not necessarily true given how Harry is able to open a portal to Hades in SG, without Hades’ help in doing so.