There seem to be some unwarranted spoilers going around that I (and everyone else) assume to be fake, so I’m going to mention the most (or least) believable of them; Jace, Advisor to the Firemind. You can find the blog here.

Here’s the text they’re supplying for the spoiler:

Jace, Adviser to the Firemind {U}{R}
Planeswalker – Jace (Mythic Rare)
+2: Put a card from your hand on top of your library.
0: Look at target player’s hand.
-7: You get an emblem with “Whenever you draw a card, Jace, Adviser to the Firemind deals 2 damage to target creature or player.”
Loyalty: 1

Taking a hint from Tibalt, he’s an extremely under-powered 2-drop planeswalker that’s completely unbalanced. Starting at only 1 loyalty leaves him open to a un-transformed delver or an exalted bird of paradise. His +2 is rather bad, putting a card from your hand to the top of your library. Perhaps if a UR Delver deck develops without Ponder in format, it may see some play. Also, his 0 gives you quite a bit of information; their entire hand. However, the fact that his ultimate is a -7 assumes that he’s going to live long enough for you to get an emblem that apparently needs him on the board to use.

Due to the wording of the -7, Jace, Adviser to the Firemind would have to be present on the board in order to inflict damage to an opponent when a card is drawn. The rest of the time, the emblem would sit there uselessly.

Hopefully, this is not our real jace that’s being released, as that would simply be depressing after Jace Beleren and Jace the Mind Sculptor. Flavorfully, it would make sense for this Jace to be Red and Blue, as the Izzet League seems to be a place where Jace would want to be, especially if Niv-Mizzet truly is a planeswalker. However, only time will tell if this is a real spoiler, but I’m certainly hoping it isn’t.