When the green witch confronts Glinda, Glinda decides to taunt her about her sister, insisting that someone should drop a house on her as well.
A boundary is not a rejection.
She is also afraid of the dark in Baum's original story for reasons unknown.
Although it is clear that Azkadellia is analogous with the Wicked Witch of the West, it is implied vaguely that the Witch of the Dark is the Wicked Witch that Dorothy, who makes an appearance as a spirit in a mausoleum, defeated in the original story.
Though Evanora offers to cover up Theodora's new appearance with an enchantment, Theodora embraces her new appearance and helps her sister attempt to kill Glinda, get revenge on Oscar, and take control of Oz.
A year has come and gone and things are finally starting to go the way I would like.