Imamate in Nizari doctrine in the context of "Fatimah"

Ismailism, known historically and among practitioners as Esotericism, is a branch of Shia Islam. Like all Shia, the Ismailis emphasize a distinction between the exoteric (zahir) and esoteric (batin) dimension of Islam, and hold that the esoteric meaning was preserved from corruption by a line of descendants of Muhammad (imams). However, unlike other Shia, the Ismaili are characterized by a unique emphasis on the esoteric that approaches antinomianism.

The Isma'ili (/ˌɪzmɑːˈɪliː/) get their name from their acceptance of Imam Isma'il ibn Jafar as the appointed spiritual successor (imām) to Ja'far al-Sadiq, wherein they differ from the Twelver Shia, who accept Musa al-Kazim, the younger brother of Isma'il, as the true Imām.

Nizari Isma'ilis (Arabic: النزارية, romanized: al-Nizāriyya) are the largest segment of the Ismailis, who are the second-largest branch of Shia Islam after the Twelvers. Nizari teachings emphasise the independent legal jurisprudence or ijtihad—though they reject legal reasoning, or usul—pluralism (the acceptance of racial, ethnic, cultural and inter-religious differences) and social justice. Nizaris, along with Twelvers, adhere to the Jaʽfari school of jurisprudence. The Aga Khan, currently Aga Khan V, is the spiritual leader and Imam of the Nizaris. The global seat of the Ismaili Imamate is in Lisbon, Portugal.

Aga Khan (Persian: آقاخان; Arabic: آغا خان; also transliterated as Aqa Khan and Agha Khan) is the hereditary title of the spiritual leader and Imām of the Nizari Ismāʿīli Shias, a branch of Islam with approximately 12–15 million followers worldwide. The Aga Khan serves as both the religious head and temporal leader of the Ismaili community, providing spiritual guidance and overseeing extensive development and humanitarian work across Asia, Africa, and other regions where Ismailis live.

The title, which means "Great Leader" or "Grand Commander," has been passed down through a hereditary line for over 150 years, with each Aga Khan believed by his followers to be a direct descendant of the Islamic prophet Muhammad through his daughter Fatimah and son-in-law Ali. Unlike many other Islamic leadership positions, the Aga Khan's authority combines religious interpretation with significant involvement in education, healthcare, cultural preservation, and economic development.

Shah Rahim al-Hussaini (Persian: رحیم الحسینی;‎ born 12 October 1971), known as the Aga Khan V (Persian: آقاخان پنجم, romanized: Āqā Khān Panjum), is a religious leader, philanthropist (through the Aga Khan Development Network), and businessman. He is the 50th hereditary Imam of the Shia Nizari Isma'ili Muslims, a branch of Islam. He is the descendant from Muhammad through his daughter, Fatima, and his cousin and son-in-law, Ali. The Qasimi Nizari Ismailis maintain that they are the only Shi‘i group today led by a living, present, hereditary Imam.

He is the second of four children of Shah Karim al-Husseini, who went by the title Aga Khan IV, and succeeded as the Nizari Imam following his father's death on 4 February 2025. He is the fifth person in the family to hold the title Aga Khan. Upon assuming the Imamate, he inherited his father's estate, which had been valued at over US$13.3 billion by Vanity Fair in 2013.