Card Captor Sakura>> The Cards
Special Cards
The Special Cards are those which cannot be defeated by the Elemental Cards. This happens because these cards are not related to the physical world but to concepts or ideas, which is why they are immune to the physical powers of the elements of Nature. The only way of defeating a Special Card is by guessing its true identity, which is to say to guess its name.
The Light & The Dark
The Light and The Dark are the most loyal servants of Cerberus and Yue, the guardians of the cards. This makes sense since the two guardians represent the moon and the sun, which are clearly symbols for day and night (light and darkness).
These two cards have some sort of deep knowledge and understanding, and sometimes they even seem to be able to predict the future. For example, when Sakura opens the Clow Book, creates a wind storm and spreads the cards, The Light, instead of escaping, enters Sakura's heart, waiting for the day she has to defeat The Dark, so as to be able to help her.
These two are two of the very few cards that ever speak, and they tell Sakura that Yue will judge her last, but she has passed their test. The Light even gives her an advice that Sakura does not understand but that later on, when she fights Eriol, it turns out to be the key to break Eriol's spell.
One last detail about these cards is that they were created at the same time by Clow, and so they have to be changed into Sakura Cards at the same time as well. Also, they are very selective when it comes to accepting a new master, and when Sakura wants to change them, the only way to make it is by combining the guardians' powers with the powers of Sakura's scepter. This generates enough concentrated power to get to the core of the cards.
The Mirror
Most people forget that The Mirror is a Special Card. Kero-chan himself says so, and it is proven when Sakura tries to use The Watery against The Mirror and it doesn't work.
Curiously, The Mirror is also one of the very few cards that ever speak. In fact it is the card that speaks the most, since she has to fill in for Sakura whenever she can't go somewhere. Let's remember that its power consists in chnaging her shape to the one of whatever is in front of her, which includes people (apart from being able to reflect things just like any other mirror).
The Mirror is the one that tells Sakura that the cards are happy to have her as their new owner. She also falls in love with Touya, who knows she is not Sakura but plays along. He is very nice to The Mirror and thanks her for looking after his sister. What's more, Touya buys her a gift for Christmas (she had gone shopping with him instead of Sakura), which was a pair of laces for her hair, which Touya guessed was long. You can see them in the Sakura version of this card.
One thing I would like to point out is that, at first, The Mirror tried to hurt Touya, knowing that he was Sakura's brother and that she was trying to capture the Clow Cards. However, Touya was very nice to her, and so, when Sakura showed up to cupture her, The Mirror immitated her movements instead of fighting, so as to help Sakura guess its name.
Let me speak of a card which is not defined as a Special Card or ever refferred to as such, but I think it should be:
The Illusion
The Illusion, though not called by anyone a Special Card, I think adjusts to the description of what a Special Card is like. First of all, it cannot be defeated by any Elemental Card. Second, the only way to beat it is by guessing its true identity, and third, it does not relate to anything physical but to concepts and ideas. By this I mean that it is not a real thing, because The Illusion makes you see whatever you are thinking of or whetever you wish to see.
