This is my preferred home for Azindel (the closest thing we have to old pre-nerf Vara, and a very fun card) so far. The deck is straightforward enough - play lifesteal units, then play Beckoning Lumen or Mask of Torment as lifeforce payoffs, then finish people off with Azindel. Dark Return does a lot of great things in this deck, including replaying Azindel the turn after it gets Vanquished, making a very large Vara, milling people out with repeated Dreamsnatcher ultimates, and simply comboing with Xenan Initiation.
I've felt like this deck has game against most other decks - lifesteal units and Theurge are great against aggro, Vara and Azindel + DR are great against midrange, and Mask and Dreamsnatcher give you some tools against control. The deck is not yet finely tuned; if you want to make changes, the slots that I would tweak are the Theurges and the interaction suite (Shakedown/Annihilate/Choice/Initiation/Banish) in the maindeck, and the Theurge and Disjunction in the market.