Sage

Sages are human reincarnations of Aita, a member of the First Civilization and the husband of Juno.

Sages are born normally with their own personality and memories, but they also possess the memories of Aita and all of their previous reincarnations. Many Sages have little trouble dealing with the dual personalities, but some struggle with Aita's earlier memories, which often manifest themselves in dreams, visions, or hallucinations. They bear a strong physical resemblance to Aita, and possess a distinctive.

A Sage's blood is required to open the passage to the Observatory, hidden in Long Bay, Jamaica, through inserting it into a blood vial. The Mayan civilization and worshipped the Sages, and Mayan ruins in Tulum, Mexico, contained a statue resembling a Sage's head.

Known Sages include Thom Kavanagh, the pirate Bartholomew Roberts, and John, an Abstergo Entertainment employee.

According to the Assassin Mentor Bahlam, there had been at least eighty Sages over the years up until the late 1600's.

Reference

 * Assassin's Creed IV: Black Flag