Clea possesses formidable abilities for manipulating mystical forces for various purposes, due to her training by Dr. Strange and her Faltine descent. At this point, Clea is Sorceress Supreme of the Dark Dimension, and her power equals that of Umar at Umar's peak. Clea finally achieved this high level of power in her battle with Umar that led to Clea's becoming ruler of the Dark Dimension. At that point, the "flames of regency," that by Dormammu's spell appears about the head of the ruler of the Dark Dimension, surrounded Clea's head. The flames, which do not harm Clea, will remain about her head as long as she is ruler. It is believed that the flames themselves may have increased Clea's power. Whenever Dormammu has been deposed and Umar succeeded him, the flames appeared about her head , and her power increased.

Presumably Clea generates great mystical energy within her own body as Dormammu and Umar do, and can draw upon it. It remains to be seen what Clea can do with her newly increased power. While she was a student of Dr. Strange and removed from the Dark Dimension, her magic, like his seemed to be derived from three major sources: personal power of the soul/mind/body (such as mesmerismand thought casting), power gained by tapping the ambient magical energy of the universe she inhabits and employing it for special effects (such as illusion-casting and energy projection), and finally, powers gained through the tapping of mystical energy from other dimensions by invoking entities of objects of power existing in those dimensions. The latter means of power is usually gained by the recitation of spells, either ritualized ones found in various mystical text or original spells invoking extradimensional assistance.

The full range of Clea's mystical abilities have yet to be seen. However, it has been theorized the Clea, ay least potentially, can now perform any magical feat that her mentor Dr. Strange or her mother Umar can. Clea's abilities are, however, limited by her amount of training and experience. It is known that Clea can form and hurl magical energy bolts with a high degree of potemcy and skill. She can use local magical energy for the conjuration of at least physical objects or for unusual luminescent effects. She has an extensive knowledge of sorcerous spells and incantations which were taught her by Dr. Strange and which invoke the names and aspects of various extradimensional power sources for very specific effects without taxing her own personal abilities.

As the daughter of Umar, a member of the extradimensional race Faltine race, Clea has a body whose density is somewhat greater than that of an Earth human. As a result, she weighs more than an Earth woman of the same height and build would.

The rate at which Clea ages is unknown. Her father has aged very slowly over the centuries, and her mother has apparently not aged at all over this same amount of time. It has been speculated that Clea is thousands of years old; however, physically, she remains a young woman.