Afro Samurai: Number 2?

I saw the Afro Samurai series and I thought it was great(gory, but great). But one thing that makes me curious is about the Number 2 in the series. I know that Justice was the Number 2 when he fought Afro's father and when he killed him he became the Number 1. Who became the Number 2 when Afro's father was killed? How did Afro's master come about becoming Number 2?

Afro became number two as a kid, but got the headband taken from him. Afro's master probably picked it off some greedy *******.