Just finished reading the fourth Uncle book,
Finale from the author of the Ava Lee series, Ian Hamilton. A bit stilted at the beginning (seems like this is a common problem for the Uncle books), but then picked up and I ended up devouring it. A solid 4, but certainly NOT the book to start the series with. First in the series is
Fate, and the
Ava Lee series, in which Uncle is an important character and mentor to Ava Lee, might be the place to start. I really enjoy both series.