Quranic basis: The Mahdi is not mentioned in the Quran — the concept derives entirely from hadith traditions and developed Islamic eschatology. This makes it theologically contested: some Sunni scholars (notably Ibn Khaldun) were skeptical of Mahdi hadiths.

Sunni position: The Mahdi is a future figure from the Prophet’s lineage (Ahl al-Bayt) who will appear before the Day of Judgment, fill the earth with justice after it has been filled with oppression, and rule for 7–8 years before the return of Jesus (Isa) and the final events. He is not a prophet (prophethood ended with Muhammad) but a divinely guided political-religious leader.

Shia position: The Mahdi is identified with the Hidden Imam — the 12th Imam Muhammad al-Mahdi, who went into occultation (ghayba) in 874 AD and will return at the end of times. This is a doctrine of ongoing divine guidance through the Imam, giving Shia theology a living (if hidden) authority structure that Sunni Islam lacks. The expectation of the Hidden Imam’s return is the central eschatological doctrine of Twelver Shia Islam.

Historical Mahdis: Numerous figures have claimed to be the Mahdi — Muhammad Ahmad in Sudan (1881, whose state fought the British), the Mahdi of the Sokoto Caliphate, and most recently the Juhayman al-Otaybi seizure of the Grand Mosque in Mecca (1979) in the name of a claimed Mahdi. Each claim produced intense theological controversy and typically state violence against the claimants.