Sire

Your Sire is the vampire who embraced you (made you a vampire).
For Ghouls we use the Sire-slot to record the ghoul's Domitor (who made you a ghoul).

A Sire can be a background NPC that is not presently living in LA or a (N)PC.
The Sire-entry simply contains your Sire's name. You can elaborate on who your Sire is in your background.

Your Sire's name is prompted during the initial CharGen stages. After this it can only be changed by an Architect.