Her name is Liliana Vess and she is a Planeswalker. She is "witty, magnetic, and unabashedly sexy." She looks like she's in her 20s but being an immortal Planeswalker, it's hard to tell. Read her story here.
So far, we don't yet the rule regarding Planeswalker. But check her out. A Vampiric Tutor and a Living Death on steroid in one card? Insane. Reanimation deck will definitely comes back.
Of course she is no Urza, or Serra, or Freyalise, or even Tevesh Szat. But she's a planeswalker nonetheless. Wizards of the Coast had finally make Planeswalkers into cards.
How did I find the card? Solve this puzzle and WotC will show it to you. And if you can't (or don't want to) solve the puzzle, I got the answer. I've done the dirty work for you. And by that, I mean that I found the answer from MTGSalvation forum.
"Here is an exclusive Planeswalker rules preview. Creatures can attack Planeswalkers. If a creature does attack one of your Planeswalkers, your creature can block it as though it were attacking you. If a Planeswalker is dealt combat damage, it loses that much loyalty."
Loyalty? What the hell is this new term mean? Only time will tell.
Here's the screenshot of the solved puzzle: