Mirage is inscrutable in her motives; Iago has apparently heard of her, calling her "Evil Incarnate", though Genie knows nothing of her due to being stuck in a lamp for about 10,000 years. She never provides any insight on herself, and other evidence is circumstantial at best. It is possible that she intends to kill Aladdin and his friends and then take over Agrabah (or the world); she certainly attempts the former several times; as mentioned, she is called "Evil Incarnate" during the course of the series, and it is possible that all of her actions are motivated simply by malice or to destroy any form of Good, as she unleashed her fire-cats on an innocent village just for growing food and she caused a civil war to prevent two countries from making peace. The only reliable evidence is from the mysterious blind magician Phasir, who appears in few episodes of the series and who seems to have some history with Mirage, though it is not expanded on. Mirage is a sadist, enjoying others' pain and relishing in their anguish and despair, seen when she taunted Wahid about his impending death in "The Lost Ones".
She rules her own etheral realm she calls Morbia, which appears to be in literal outer space in an asteroid field where her home, a sphinx-styled temple, is located.
She seems to have no real regards for her minions as she was willling to let die Wahid, a boy who fell victim to the offer of the El Katib, simply for his disobediance, and she left the rest of her El Katib minions to die from the setting of the full moon after Amal defied her. And her firecats feared her wrath when she was angered they failed in burning a village to the ground.
Mirage is a most dangerous sorceress, with power over illusions, dreams and shadows, her magic powers are enough to create a mirage of Agrabah, its people and Aladdin's friends. This, combined with her stunning keenness and ruthlessness, makes her a dangerous enemy. She has demonstrated many magical abilities, such as creating feral cat-monsters made entirely of fire that grow bigger by feeding on fear, scrying, slashing Genie to pieces without even touching him, flying, teleportation, turning children with true potential for evil into monsters and reverting the change, creating a lotion that transformed Jasmine and Aladdin into snake-like humanoids, controlling the elements, energy bolts, shapeshifting (or at least glamouring), summoning natural disasters, some degree of omnipotence, etc. Mirage is very knowledgeable in arcane lore, especially regarding to dark arts as she exploited a magic music box to make everyone in Agrabah fall asleep and turn them into her sleepwalking minions, she created an indestructable obelisk of black stone whose shadow would wipe anything caught in it out of existence.
True to her name, Mirage is a skilled illusionist, being able to make an illusion of Agrabah, its people, etc. But while Mirage's illsions are convincing they're not perfect. And she is known to disguise herself with illusions, a power called Glamouring, to completely disguise herself as another, and has fine acting skills as she posed as a Sultana to fool the Sultan and everyone else for at least a week before she deliberately blew her cover, she disguised herself as a merchant to sell Jasmine a lotion without raising any suspicion, and even disguised herself as Genie.
It is also implied that Mirage is capable of creating new realms or dimmensions, such as her own realm Morbia nd the Shadowrealm, where she kept her minions of the El Katib. If not than she is capable of inter-dimmensional travel, and even that is limited as she is only able to bring the legion out for three nights once every seven years though whether or not she can of her own will is unknown.
Mirage is extremely powerful, being on an equal footing with Jafar, (as a sorcerer) Genie and Mozenrath. She wields many common powers such as flying, teleporting, travelling through dimensions, shapeshifting, making images or avatar of herself appear out of nowhere, and seeing or talking where she isn't physically present. She controls illusions to the point of being able to create illusionary places which she can manipulate; and she can warp reality to the point of creating fake replikas of an entire city. She controls shadows as well, as she is able to generate objects whose shadow destroys everything it comes in contact with, and rules the Shadow Realm, where the evil El Katib are dwelling. She also has the ability to summon nightmares in sleeping minds.
She controls several monsters such as fire cats and the El Katib, and she exert an influence over everything evil. She knows every monster and demonic being, as well as every evil magical artifact that exists in the world, she knows where to find them and she can control everything they make happen. She can also use "traditional" sorcery such as spells and potions.
Mirage is never seen actually fighting but she masters several magical attacks: a claw swipe which sends slicing waves of green energy (her most used attack) / green energy rays fired in rapid succession / green bolts of lightning / she surrounds herself with green and black lightning. She also displays great physical strenght, being able to send Genie flying with a mere backhand.