Imamate in Ismaili doctrine

The doctrine of the Imamate in Isma'ilism differs from that of the Twelvers because the Isma'ilis had living Imams for centuries after the last Twelver Imam went into concealment. They followed Isma'il ibn Ja'far, elder brother of Musa al-Kadhim, as the rightful Imam after his father, Ja'far al-Sadiq.

Source: Wikipedia — Imamate in Ismaili doctrine (CC BY-SA 4.0)