Just as Merida leaves with the cake, the witch realizes she forgot something very critical about the spell but is too late to tell Merida. In exchange of buying her entire stock, Merida convinces the witch to give her a spell in the form of a cake, to change her mother.

The witch tells her that she's not a witch due to too many unsatisfied customers and tries get rid of Merida with floating knives until Merida offers to buy all of her carvings. But Merida rapidly realizes her real nature, after seeing a broom moving by itself, a speaking crow, and other abnormal wonders. The Will O' the Wisps lead Princess Merida to her hut, and the woman insists in presenting herself as a simple woodcarver. The Witch lives the life of a wood carver and uses her knowledge in magic to help her in her work.

She was able to change the appearance of her shop to where she uses her magic and is skilled in brewing potions. She possesses telekinesis and was able to move her broom without touching it and levitated all the sharp objects in her shop.

The witch from brave wikia