Some schools gave scholarships to good families who fell on hard times. But of course that required a lineal as proof that you were a worthy investment.”
-- Sai (chapter 4)

Importance: Sai is revealing details about this society to the reader, including that a lineal is necessary to open virtually every door to good opportunities.

Even if Mud and Catfish got lucky and one of their cons worked, it wouldn't last. We could live in a palace and there would always be something rotting in the corner.”
-- Sai (6 )

Importance: Mud and Catfish are trying to convince Sai to help with their new idea to steal armor that would be worth a lot of money. Sai believes that the two men are dishonest and dishonorable at their core, meaning they would remain that way even if they were rich.

I doubted she had a background as low as mine, but whatever her station was in life, she...
-- Sai (chapter 14)