Oh come on everybody, don't stare at me like that! No, I'm not mad, crazy, insane or whatever you are going to ask. I'm serious. Ok, at least wait until you see what I mean.
Do you remember in The Lightning Thief, everybody thought Hades was bad? He sent monsters after Percy and everything, but he was NOT the BBG. He only wanted his Helm of Invisibility back! So this is my theory: the mistress is not evil. She only wants something that should belong to her, or she has been taking conselhos from a very evil guy (remember King Minos?)
I know what you are going to say. That has already happened in TLT, R.R won't repeart himself. But will he? As you guys may have noticed, the TLT and TLH books had a similar beginning. Was it just a coincidence, or did R.R do it on purpose? You never know...
Yes, I'm going to explain what made me think so. First, I reread the sample chapters and found a bunch of mysteries in only 2 chapters. OMG, R.R is a genius! Thank the gods he isn't on the bad side!
The first thing I noticed is the way Jason uses Roman terms. Are Greek and Roman gods the same, or they are 2 parrarel worlds? Ok, first I'll tell you where the Romans came from. After Troy was defeated, the great hero Aeneas led the survivors to Italy, and Rome was founded por his great-great-grandchildren. Therefore, in my opinion, the Greek and Roman gods are the same. After they left Greece, the Trojans/Romans invented there own names for the gods and even some new myths.
Prince Aeneas, leader of the Trojans, was a son of Aphrodite and Anchides, a cousin of King Priam. He was a demigod and a favorito of Apollo. The gods saved him when he was almost killed por Achilles and told them to stay away from the battle field.
Why am I telling you these stories about Aeneas? I'll show you why. Julius Ceasar (I have a hunch that Jason's sword used to be his) is believed to be descended from Aenaes. Now you see the connection?
Now look at this: "You have no idea how many enemies you've awakened, half-bloods. My mistress will destroy all demigods. This war you cannot win."
That was what Dylan said when Jason killed the other two Anemoi Thuellai. What made the mistress want to kill ALL demigods? A couple of storm spirits? No, I don't think so. She must have hated demigods before.
And this is another thing I found quite interesting. How come the mistress knew about the camp's "special package"? Was she one of the camp councelors, did she have a spy at camp, or was she the one who delivered the package?
Aenaes, Roman mythology, demigods, all these clues lead to one huge event: The Trojan War. Though Zeus told them to stay away, many gods and goddesses took part in the Trojan War. And I found among them one goddess who has the ability to know what she wasn't supposed to know and some reasons to hate heroes.
Thetis, leader of the Nereides. As a daughter of Nereus the old man of the sea, she was given the gift of prophesy. Her husband was King Peleus, son of a nymph (do children of nymphs count as demigods?). Was she happy? No of course she wasn't. Both Zeus and Poseidon used to amor her, but they had her marry a mortal because according to a prophecy, she was destined to urso a son greater than his father. Her son Achilles (who was also a demigod) was indeed one of the greatest ancient heroes. Did she like the Trojan War? No, I don't think she did. However she attempted to protect her son, he died in the war which was caused por Helen, a demigod daughter of Zeus, and which attracted extremely many heroes. Well, her life was messed up por a bunch of heroes, right? I don't think that's a good reason to hate demigods though, but good intentions can turn bad if your advisor is planning something evil.

Of course I'm not going to throw this theory out without any evidence. She has the gift of prophesy, which explains why she knew about Jason. And another bit of evidence I have: in the myths, she had silver feet and dark hair (In The Battle of the Labyrinth, Achilles had black hair too). Does it sound familiar? No? Then check this out (this is when the mistress called Dylan back): "Above them, the storm exploded into a full-force gale. Cracks expanded in the skywalk. Sheets of rains poored down, and Jason had to crouch to keep his balance. A hole opened in the clouds - a swirling vortex of black and silver."

So why did she kidnap Percy and Piper's dad? I thought a little and came up with a very crazy idea: She had once given birth to a son who was mightier than his father. Now she is going (or Dylan told her) to do that again. To defeat all demigods, she must find a father for her son, a very powerful father. That's why Percy disappeared, and very probably that happened to Piper's dad too.

And this is the most important part: what happened to Jason? He was once mentioned in PJO (The Titan's Curse, chapter 6) and he had memories about camp, so I think he used to be at Hermes cabin. Then he was claimed and left camp to live with his father. Boreas is believed to live on the island Thrace, which belonged (I think so) to Rome, which also explains why Jason used Roman terms. There he accidentally saw or found out what happened to Percy. Unfortunately, Dylan knows that too, and of course he doesn't want anybody to know their little secret. Jason escaped, lost his memory on the way and with the help of some gods he arrived at the school bus three days later.

Then why is Dylan helping Thetis? I think I know that too. Maybe he was sent por the BBG, or maybe he wants to use her. When he was fighting Jason, he mentioned some rewards, right? So that is what he wants: he wants her to choose him. The word "mistress" can also mean "girlfriend". It's not so difficult to figure it out. He wants to take revenge on the gods, but he doesn't have enough power. He visits Thetis, suggests the plan and persuades her that demigods are bad. Thetis was too sad after her son's death to think properly, so she agrees with the plan, but she decides that a demigod will be better. Dylan doesn't want to give up his plans, so he tries to kill all the "candidates" (that's probably the great danger Piper's dad is facing in Piper's dreams). How do you like that?

So this is the last question: If Thetis is really the mistress, will she be the BBG of the series? No, I don't think so. Thetis is not a bad goddess. She saved Hephaestus when he was thrown from Mount Olympus. However, in some myths, she was brought up por Hera, so... well, you know what I mean. Hera doesn't seem to like demigods. Anyway, as I have mentioned before, I don't think Thetis is bad. Dylan is. She'll come to her senses soon.

OK, so that's my theory. Maybe it's not very good and the evidence is not very persuasive. Anyway, only R.R knows exactly what will happen. All we can do now is keep waiting and guessing. If you have anymore theories, please comment.


aleatório fact: On her wedding, Thetis was given a pair of immortal cavalos which were sons of Boreas and (supposedly) Jason's half-brothers. If she's the mistress, which side do you think they'll take?