key figure

n. an important person in an event; a person central to an event. Sam is not exactly a key figure, but he can lead us to Mr. Big.

Name	Pronounced	Usage
Senan	-	Irish
Burton	BURT-ən	English
Haris (2)	-	Greek
Vratislav	-	Czech, Slovak, Medieval Slavic
Seraiah	-	Biblical, Biblical Hebrew
Clemence	KLEM-ənts	English