Cassian

The man who offers Ivy the job that starts her relapse. He does it casually, and that is what makes it work.

The offer

He runs small jobs, and ran them alongside Ivy's crew "back when she was young enough that running jobs had felt like a game rather than survival" (ch. 225).

He approaches her on her third day back with the tone of someone expecting a no:

CAS: There's a job. Nothing big. A merchant on the east side, keeps too much coin on hand and not enough sense to hide it properly. Could use someone with your hands.

He never argues, never persuades, and never mentions who she has become except once, flatly:

CAS: You're famous now, aren't you. One of the big heroes. IVY: I don't know what I am right now. CAS: Fair enough. None of my business anyway.

That is the mechanism of the whole arc. The quarter does not tempt her. It just declines to ask.

What he is like to work with

Fair. He splits proceeds "with the same casual fairness she remembered", and his review of her first job back is two words plus a compliment:

CAS: Good as you ever were.

He organises most of the crew's work across the three weeks that follow.

How it ends

It does not end with a confrontation. Ch. 231:

She did not go back to Cassian's crew the next morning. [...] It felt instead like simply not showing up, the particular quiet finality of a choice made once and not revisited.

He is never told. Ivy's only account of him afterwards is to a nine year old:

IVY: Not the person who ran jobs with Cassian for three weeks pretending that was the whole of it.