Half a year was not a short time for Aries. During those months, not only she was busy acting as the empress and mother of the nation. She never failed to study and practice her power with Isaiah. Initially, they had no idea what Maleficent could do; no one knew.
Over time, Aries slowly figured it out after going back and forth between that vision and that man, who called him her soulmate. With the help of that strange man and the witches from the night council, Aries got a good grasp of her power.
Soul.
What made Maleficent dangerous of all was that she had the power to trap people in a world she could create. It didn't matter if they were humans, vampires, werewolves, or whatever creature. For as long as a person or anything had a soul, she could take them and leave their bodies in the real world.