Usul Fiqh in Ja'fari school in the context of "Nizari Isma'ilism"

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.