Reporting in on the
Succubus series by Richelle Mead.
Really almost nothing in the way of "EC", save for a scene in book 3, but that's more unrealized potential at this point.
It's only up to 4 (of 6) so far with the 5th coming out March of next year, so it could play out further.
Not a whole lot of transforming unless you count shape shifting to various degrees.
No where near as much sex as you would expect from a series based around the immortal life of a sex demon, but there's at least a couple scenes per book.
Either way, the series has been fantastic.
It's been
a lot of fun and I highly recommend it for anyone who's a fan of urban supernatural yarns.