It's got to be a Blue Mage.

1. In the preview trailer for the expansion it shows a red woman, and a blue man fighting on top of some huge statue (2 min mark of the trailer)
2. Spiderman wears Red (Red Mage) and Blue (blue mage)
3. Spiderman absorbed the powers of the spider when he was bitten. A Blue Mage absorbs the powers of an enemy when they attack him/her.