Magic Mirror

The Magic Mirror is a minor character in Descendants and Snow White and the Seven Dwarfs. The Evil Queen use to hold ownership of the Magic Mirror, and primarily exploits its power to ensure that she remained the fairest in the land.

Snow White and the Seven Dwarfs
Everyday, the Evil Queen asked the spirit inside it whom the prettiest person in her kingdom is. For years it said that she is the fairest. But eventually, it said that her stepdaughter Snow White is now the fairest of all. Out of jealousy, the queen orders a Huntsman to kill her and bring back her heart in a box she gave him. Then the Magic Mirror ratted him out for bringing her a pig's heart instead.

Descendants
In this film, the Magic Mirror is reduced to a simple hand mirror as the Evil Queen was only able to hold onto a shard of her former possession. Evie, the daughter of the Evil Queen, is given possession of the Magic Mirror when she leaving for Auradon. Like most previous versions, it can answer any question. This time it showed the answer on the glass and must be asked a question in rhyme. Some questions posed it are "Where does Fairy Godmother's wand stand?" and "Who is the biggest jerk in the land?"

Descendants 2
The Magic Mirror is mentioned in Descendants 2, when Evie was trying to convince Mal to donate her spellbook to museum.

Descendants: Wicked World
The hand mirror that contained a shard of the Magic Mirror started the short animated episodes off when Evie asked it to show her the future. To see "what happens when" their "stories unfold".

Evie doesn't use the Mirror or it's magic like she did in the film, both she and Mal are trying to be good by not using the mirror or Mal's Spell Book. But Evie did talk to it in Voodoo? You Do, after looking at herself in a larger mirror in a shop on the Isle of the Lost. She wanted to make sure that both the mirror and the reflection it gives of her know that she stills loves them: and so the Mirror itself wouldn't get jealous. However Evie does use it's magic in Mal-lone, as she asked it to show her where Zevon is.

The spirit of the mirror's face/head can also be seen as a large mask in the Facilier shop as Mal, Evie, Ben, and Audrey walk into it.

Personality
Not much is known about the mirror except that his sole purpose is to serve whoever may own him at the time. Whilst he is antagonistic on various occasions, he is not intentionally evil, as he is forced to obey the Evil Queen due to being her slave. He does not hesitate to tell the truth to the Queen when it is revealed that Snow White was still alive.

Isle of the Lost: A Descendants Novel
In the book, there is a Magic Mirror standing in a room at the forbidden fortress on Doom Island, however: it is unlikely this is the Magic Mirror, since that mirror is broken and this one is whole. Also, it would be unlikely for the Evil Queen to have the Magic Mirror on Doom Island. And the Evil Queen is last seen with it there and dies shortly after.

CJ's Treasure Chase
CJ Hook tried to use it to locate something, but she ended up learning that it only worked for Evie and her mother.

Trivia

 * In Fairest of All: A Tale of the Wicked Queen, it's revealed that he was Evil Queen's father before he died and when he was still alive, he was a mirror maker.
 * There is a second object from Snow White and the Seven Dwarfs. The Heart Box which the Evil Queen wanted to put Snow White's heart in, appears in Descendants as a purse of Evie's.
 * The magic mirror was mentioned in Descendants 2 when Evie was trying to convince Mal to donate her spellbook to the museum.