Unicorns are magical, one-horned creatures. At least one is housed inside the Library.
It is unknown what an in-universe Unicorn can do.
Real Life CounterpartEdit
Unicorns are mythological, one-horned creatures (usually horses) with magical abilities. They have been revered as symbols of purity, grace and magic since ancient times, and are said to only show themselves to humans of extreme purity and goodness. Their horns are said to be able to purify poisoned water, a trait which lead many real-world people to search for them back in the Middle Ages.