Melchizedek (Priest living at the time of the Patriarchs)

Genesis names him once and never explains him, a king and priest with no genealogy, blessing Abraham out of nowhere (14:18-20), which is exactly what later readers found so strange about him (Hebrews 7 leans hard on that silence). Josephus is more matter-of-fact: he glosses the name itself ('the righteous king') and identifies Salem as the city that would become Jerusalem.

Melchizedek was the king of Salem and a priest of God Most High who blessed Abraham and received a tenth of his war spoils in Genesis, appearing without any recorded genealogy, birth, or death. The Psalms later describe a coming king who would be a priest forever in the order of Melchizedek, and the New Testament book of Hebrews builds an extended argument from that same silence about his origins, using Melchizedek's priesthood, older and greater than Israel's own Levitical priesthood, to explain how Jesus can be a priest despite not being descended from Levi.