Illusion Casting is the ability to alter the perceptions of other beings, allowing users to make others experience what they desire. Illusions are tricks of the mind and can affect all senses except for touch, making them appear very life-like.
Illusions can be used in various ways. In its basic form, it can be used to make other beings, see, hear and smell what the user desires. Illusions can also be used to hide one's presence from others by casting an illusion around themselves.
Illusions require skill to be cast successfully. Users that have mastered illusions are capable of seeing through and negating the illusions of others. For example, Ambrose was able to see Arthur despite the latter hiding his presence.