Zatanna Zatara is the daughter of the world's greatest magician, John Zatara. She was searching for her father's spell book for years after it was bought by Lex Luthor. After recovering the book, she is now researching spells to become a better magician.
Zatanna possesses powerful magical abilities. At first, her abilities were limited to granting a person's wishes of whatever that person most desired at the moment. However, Zatanna's ability to grant wishes only works on others; it does not work on herself.
After finding her father's spell book, Zatanna's powers were increased and she learned that, by speaking words backwards, she could conjure spells. By speaking "leets yb dnuob!" ("Bound by steel!"), she was able to imprison Oliver Queen within chains that suddenly appeared. With the book, Zatanna has access to the wealth of magical spells, including one that can resurrect a person from the dead, provided that another life is sacrificed in exchange for theirs.
Zatanna also has the ability to appear and disappear at will, and the Book of Zatara is drawn to her; when Oliver was about to burn it, it flew to her hand.
Zatanna utilized two spells on Clark; one being "doom eht tes!" ("Set the mood!") which conjured lots of candles surrounding both Zatanna and Clark, and the other spell being "wolf eht htiw og!" ("Go with the flow!") causing Clark to kiss Zatanna in a very intimate way. Later on, she said "Detaeper eb ton llahs rehtaf eht fo nis... dnuof niaga ecno s'eh, tsol ecneconnI!" ("Sins of the father shall not be repeated... Innocence lost, he's once again found!) to reverse the curse on Alec Abrams being "Warrior Angel/Devilicus".
Zatanna is a powerful sorceress whose abilities are apparently genetic. As a tribute to her father and as a focal point, she usually casts spells by speaking verbal commands backwards. She has also proven capable on many occasions of casting spells by speaking normally, and, in rarer occasions, the ability to use magic for simple tasks without speaking. On very rare occasions, Zatanna has cast spells by writing them in her own blood rather than speaking them aloud. It's used as a last resort, only to heal from severe physical damage preventing her to speak, like having her larynx mangled by a bullet, or her mouth magically erased by her own powers. The only magic command issued in both cases, Heal me, had to be spelled backwards, as she were speaking (laeH em).
Overuse of her magical powers can deplete them to the point that further use of them starts to put a considerable strain on her physical well-being: as with other magical users, the only way to restore her waning powers is an extended period of rest.
Even if not as precisely as Madame Xanadu, Zatanna has proven herself able to call upon tarot reading for insight or divination. Apparently, such a task does not require verbal incantations, spoken or written, at all, nor is it tied to a specific tarot deck.
The limits of her powers have never been clearly established. She is often depicted working alongside the most powerful magic-users on Earth, including Doctor Fate, Madame Xanadu, and Captain Marvel. She has used her powers to command elemental forces, heal, transmute and transmogrify objects, manipulate minds, and attack her opponents with energy blasts. She has resurrected the city of Metropolis from ruin, merged Aquaman's spirit with the entire ocean in the finale of the "Obsidian Age" story arc[volume & issue needed], and manipulated time and space. During a portion of her initial tenure with the Justice League, her powers were more limited, consisting in the manipulation of fire, air, water, and earth. Furthermore, her powers seems tied to her self-confidence, as the long series of blunders described in Seven Soldiers left her both emotionally and psychologically shattered, powerless, until she was able to restore her lost confidence.
Zatanna is a skilled illusionist, showgirl and stage magician even without resorting to her innate magical powers. In fact she considers part of her "training" exercising sleight of hand tricks, and she claims to have invented a variation of the three card shuffle game called the "Zatara shuffle", in which she's so fast and precise that, even without resorting to cheating, only skilled gamblers like Selina Kyle are able to follow the movements of her hands.
On Bruce Wayne/Batman: In Detective Comics #833 (August 2007), it is stated that Zatanna's father was a friend of Thomas Wayne. Zatara trained Bruce Wayne in the art of escape; and Bruce and Zatanna were childhood friends.
I am not Zatanna, nor the the lovely actress who plays her, Serinda Swan. I have no affiliation with the CW, Smallville, DC comics or anyone with any real power or money, so please don't sue, okay? This is just for fun. No money is being made, blah blah blah.