That just makes it sound like there's a 'yet' in that sentence.

[ Not a member of the Thieves — yet. But inevitably, as things approach the their ultimate destination ... ]

Though maybe that isn't the case. Maybe it's only Ren you care to work with. You have talked a decent amount about working with him specifically and not much about anyone else.

[ though maybe that's just because Ren's the only other person Akechi knows who's here? ]