The Grand High Witch of All the World, or simply The Grand High Witch, is the main antagonist of Roald Dahl's bestselling book The Witches, as well as its film adaption. She is the ruler of The Witches, a race of demons who have made it their duty to kill and torment children, who they hate because they smell bad to them. The Grand High Witch has taught other witches magic to rid themselves of children, including turning them into statues, transforming them into various animals, and turning them into hot dogs for their parents to eat. The Grand High Witch has a hideous face, so she hides it under a realistic mask. In the film she is played by Angelica Huston.
The Grand High Witch booked into a hotel in disguise and her name was Evangeline Ernst. The other witches also booked in to hold a meeting at the hotel. The day before the meeting, The Grand High Witch made her first move on a child named Bruno Jenkins and gave him a chocolate bar and then told him she would give him more if he came to the meeting. The next day the Grand High Witch called the other witches for the meeting, not knowing that a young boy named Luke Eveshim, grandson of former witchophile Helga Eveshim, was hiding inside. When she thought no one was there, she ordered the other witches to remove their wigs, gloves, and shoes. The Grand High Witch removes her mask, revealing a grotesque and deformed face.
After berating the other witches for their failure to wipe out all the children in England, the Grand High Witch demands that every child in England be eliminated. When one witch expresses astonishment at a seemingly impossible task, the enraged Grand High Witch incinerates her to prove a point to the other witches. Afterwards, the Grand High Witch reveals her new potion, the Formula 86 Delayed Action Mouse Maker, which transforms whoever consumes it into mice. The Grand High Witch explained her plan to have all the children in England be turned into mice and be killed by the adults via putting the formula into candies. She also revealed that the chocolate bar she gave to Bruno contained the formula. Soon afterwards, she brought Bruno onto the stage, where the other witches witnessed him transform into a mouse.
Having shown her plan to be a success, the Grand High Witch announced that the ancient witches, who had served her for many years, would come and receive the readily-prepared formula, as they were too old to get the ingredients themselves. As the meeting came to a close, Luke, who had hoped to escape, was discovered when one witch smelled him. The Grand High Witch ordered the other witches to capture him and take him to her. The witches obeyed and the Grand High Witch poured the formula into Luke's mouse, transforming him into a mouse. Believing Luke to have been disposed of, the Grand High Witch returned to her hotel on room 454.
Some time afterwards, the ancient witches arrived to receive the formula. As the Grand High Witch let the witches in, Luke, though still a mouse, infiltrated her room and managed to steal her formula without the Grand High Witch noticing. Afterwards, the witches, including the Grand High Witch, arrive for dinner. However, Luke pours the contents of the formula into the witches dinner. As the witches eat, the formula causes them to be turned into mice. The Grand High Witch, possibly due to her immense power, takes a longer time to transform and, upon being exposed by Helga, advances on her with the intentions of killing her.
Before she can murder Helga, Bruno bites her, distracting her and causing the formula to finally take its toll. As the Grand High Witch begins to transform, she is berated by Helga for her cruel actions. Enraged, the Grand High Witch declares that she isn't finished with Helga yet, but transforms into a mouse. Helga manages to trap her under a glass cup before alerting Mr. Stringer, who had ordered the kitchen staff to eliminate the recently-transformed witches. Mr. Stringer, upon being told that the Grand High Witch is especially contagious, removes the glass cup and slashes her witch a butcher knife, killing her and ending her reign of terror for good.