I can't remember how many kids he started up with. Many of them were killed, tortured for disobeying orders, or sometimes because they'd failed to make progress.
16 seconds sound clip from the The Avenging Eagle movie soundboard.
You can hear this line at 00:17:42 in the Blu-ray version of the movie.
Quote context
[...]
- And any man who shows any kindness, he will order them torture to death.
- So then, his orders are always obeyed, because disobedience means death and a painful one.
- When I was seven, I was sold to the Iron Boat clan. I followed Yoh Xi Hung...
- I killed and looted, and gradually all my human instincts just disappeared.
- Hmm, that's right. But still, right now he only has 12.
- You're right he has. I must admit, you tell a good tale.
- So tell me why'd you leave Yoh Xi-Hung?
[...]