What Is Magic

Once Upon a Time is, obviously, a fantasy show in which magic is a strong element of the story. This entry attempts to tease out the ground rules for how it works, while other entries go into details.

Requirements for Magic

Magic has two requirements. The first is ability, which can be inborn or acquired via a curse such as the Dark One's. The degree of power varies from one person to another and can be increased through practice. Natural ability appears to run in families.

Note: Purely object-based magic, such as mixing potions, can apparently be done without having any native powers at all (as shown by Belle, 5.06)

The second requirement is ambient magic on which this ability can work. This varies a great deal from one realm to another. Magic in the Enchanted Forest is abundant. 1.07 establishes that there is a relationship between the availability of magic there and the presence of diamonds. Diamonds are mined by dwarves and can be milled into fairy dust.

"Magic is in short supply around here, and dwindling by the minute." (Rumple 1.21).

Magic on Earth, on the other hand, is thin and unpredictable. Emma's abilities are expressed seldom and haphazardly, and Rumple and Regina can't use magic at all. However, some aspects of magic operate even in its overall absence, notably true love's kiss and the price of magic (for more on that, see The Rules of Magic).

Rumple's use of the True Love potion in the well provides a local infusion of power, siphoning magic from the Enchanted Forest to Storybrooke (1.22). A brief re-learning curve for Regina follows (2.02) before she is able to use her power again.

"Magic here is unpredictable." Regina (1.22)

"No wand, no fairy dust. Matters are complicated now." Blue Fairy (2.01)

This new power source is contained within the boundaries of the original Dark Curese; once he leaves the Storybrooke limits, Rumplestiltskin can't do magic (2.13).

Following the return of magic to Storybrooke, the dwarves begin looking for fairy dust diamonds (2.04). Upon their discovery (2.07), the Blue Fairy says, "Theyr'e back. The magic brought them back." (Did Rumple's use of the True Love potion create diamonds, which are the actual source of magic? Or did the presence of magic lead to the occurrence of diamonds?)

Rumple and Regina go into the mines and use all of the diamonds to charge one of his stolen fairy wands with power sufficient to destroy anyone coming through a portal from the Enchanted Forest. The removal of the diamonds doesn't affect the ambient magic level in Storybrooke, however, and the Blue Fairy is able to charge her wand, using magic to try to break into Gold's shop (2.15) and to turn August back into a human boy (2.18).

In an attempt to remove magic from Storybrooke again, Henry plans to blow up the well (2.17), but there is no indication that this would actually have worked. By the time 3.07 takes place, there is more fairy dust found in the mines, according to the Blue Fairy.

How Does Magic Work?
 
Many forms of magic are accomplished through simple will. When Rumple guides Emma through showing Pongo's memories, he just tells her to "will it" (2.10).  No preparations, incantations, etc. are required.

"Conjuring magic is not an intellectual endeavor. It's emotion. You must ask yourself, why am I doing this, who am I protecting? Feel it" (Rumple, 2.16).

"Magic comes from emotion. Simply think  of a moment that makes you seethe with anger" (Rumple, 3.16).

Other magic requires tools and/or ingredients. There are written spells as well, particularly for curses. The first we see of a spellbook is in 2.02, when Cora uses hers to free Regina from the barrier spell she cast to keep her daughter from running away. In 4.14 we find that Maleficent also has such a book, which Cora came to possess as well.

In OUaTiW, the school of magic practiced by Jafar appears to rely heavily on material ingredients and spellbooks, although some of it is will-based.

Elemental magic is introduced with Elsa and her ice powers in 4.01. She has always believed herself to be the only one (4.02) who has this particular manifestation.

Magic in the Underworld

Magic seems to work the same in the land of the dead as it does in any other magic-accessible environment (5.12), but we are later told that it’s a little bit different. Regardless, Emma (5.13) and Rumple and Regina (5.14) are able to do magic after a brief adjustment period.

Magic in the Land Without Magic

When Ingrid comes to Earth, she is unable to do any magic. Once she reaches Storybrooke, she is able to manipulate memories using a stone from the rock trolls.
Walsh is able to transform to a flying monkey, and is somehow able to reach New York in the first place.

There is some magic present on Earth outside of Storybrooke. Episode 2.18 introduces the Dragon, the only Earth-native magic-user we have met so far (assuming that he is in fact an Earth native and not a traveler from some other land).

August goes to the Dragon to see if his turning back into wood can be reversed. He knows that August is Pinocchio and claims that he can help him. He needs an item of great value, "something close to your heart, something that cannot be replaced", and asks for the string August wears around his neck, one of the original puppet strings Gepetto used to animate him. He also needs ten thousand dollars, which August, upstanding fellow that he is, steals from Tamara. The Dragon offers him a vial of glowing red liquid. "What's in this bottle can stop you from turning into wood, yes. But only you can cure yourself [of being a dishonest jerkwad]". August hands over the money and takes the bottle. Tamara gets it back from him. She later tells the Dragon that she analyzed the contents and found that its contents were not Earthly elements. (Did that happen, or was it part of Pan's charade?)

Although you cannot create new magic in this land, you can bring magic with you (4.17). Zelena gave Walsh with a few odds and ends, which are still in his shop. She has a magic pendent that lets her assume Marian’s shape.

Magic or Anti-Magic?

The muddle that was the late S2 plot resulted in an organization that claimed to be an enemy of magic. Owen had traumatic early experience with magic via Regina. We don't know what motivated Tamara's quest to find and destroy magic-users, though she does say that magic is "unholy" and "doesn't belong in this world" (2.21). We know that she has a kind of super-tazer, which she uses to kill both the Dragon and August. That it works on the latter despite him being made of wood suggests that it has anti-magical or super-magical properties.

Although Owen and Tamara were actually working for Peter Pan, that connection remains confusing. There doesn't seem to be any reason for Pan to have recruited and equipped people with a general grudge against magic over a number of years, if what he really wanted was to find the Truest Believer. What good did destroying Storybrooke do him?

We don't know when the organization as such started vs individual efforts, what they did before the curse broke, who else was involved beyond the two of them and the Darling brothers, or how the charade was maintained across worlds (although it seems that Pan's shadow must have put in some serious inter-realm mileage). Did Pan have something magical that can talk to a cell phone across realms?

Tamara says, "We know how to kill magical creatures" (2.20). Owen thinks that the bracelet Hook had from Cora now contains anti-magic gadgetry, "the toughest metals and machinery known to man" (Owen, 2.20). There is no noticeable effect until the wearer actively tries to use magic. Hook uses a similar device against Maleficent. Pan later says, "I made this cuff, you know" (3.11), so it presumably is just a matter of his own magic overpowering other magic.

We do get this tidbit from Owen: "Do you think Storybrooke is the first time that magic has crossed over?" Again, this could have been part of Pan's smokescreen, but why would he go to the trouble? Owen and Tamara eventually bring Henry to Neverland in the belief that he will be instrumental to them in destroying "the motherlode of magic" (Tamara, 3.01), though of course this is not what Pan is after.

Rumple uses the anti-magic bracelet on Pan (3.11), but being of his own making, it doesn't work on him. Pan puts it on Rumple, on whom it does work. Presumed lost when Rumple vanished and was reconstituted from the vault.

That bracelet or another one still exists (the one Hook used against Maleficent?), and was later used to restrain Zelena (4.20) when she was returned to Storybrooke.

Dark vs Light Magic

Up to S3, most non-fairy magic is explicitly identified as "dark magic." An exception is made for good fairies and their fairy dust. (Dark fairy dust is a thing that exists as well.)

S3 (3.19) formalizes the concept of light magic, "magic created from love" (Glinda). Zelena's magic, like Cora and Regina's (up to 3.20), is fueled by negative emotions, by anger. It is claimed that she can only be defeated by the most powerful of light magic. This is assumed to be Emma, until Zelena removes her power through the curse on Killian.

Henry (3.20) says that Regina was unable to defeat Zelena before, because she was using dark magic. True Love's Kiss is identified here as Light Magic*, so her being able to kiss Henry means that Regina can use light magic as well as dark. She blasts Zelena with this power at the time portal, forcing her to drop Rumple's dagger and allowing Regina to take her pendant.

Rumple tells Emma (4.08) that he knows a spell that can do away with Light Magic and leave her powerless, but he is lying, and plans to feed her to the Sorcerer's Hat.

If you are under the curse of the Dark One, apparently any magic you do is automatically Dark Magic, although there is some wiggle room here. At times it seems like Emma is using Dark and Light at the same time.

* If True Love's Kiss is light magic, then Rumple can do it too, in theory, along with anyone else who is capable of feeling love. Given that even Pan had a "thing he loved the most" sufficient to power the Dark Curse, this doesn't actually seem to be setting a high bar.