This is primarily a Harad deck, built around Kahliel and the full set of Harad allies. The main strategy here is to get those expensive Harad allies out as quickly as possible. This is facilitated by plenty of resource help: Grima, Keys of Orthanc, Steward of Gondor, and Captain's Wisdom. Erestor provides the card draw to make sure you have an optimal start and a chance to grab both these resource tools and some allies to play. A Very Good Tale helps with accelerating the playing of allies when you already have a couple on the table.
From there, Erestor's role is to help you draw through your deck as much as possible in order to make maximum use of Kahliel's readying ability. You should be able to draw at least one duplicate copy of a unique Harad ally fairly often, which will allow you to ready Harad characters. The rest of the deck consists of some generally useful allies, with Steward of Orthanc being a real star as a source of card draw, solid willpower, and help in buffing the Isengard Messengers.
Other than that, there are a few toolbox items to help you out, with Protector of Lorien helping to discard excess cards. One potential combination is to put Sword-thain on Jubayr, along with Protector of Lorien, but I haven't invested too heavily in that possibility. It's more of a fun option if it falls into your lap. The final piece to note is that A Good Harvest/Will of the West are included to reshuffle your deck when needed (as well as for some resource smoothing).
I've never tried the Good Harverst/WotW combo in an Erestor desk. I normally opt for Song of Travel. Without playing this myself, I have to ask: What if you don't draw those two cards together when your deck starts getting empty?