Eldrazi
The Eldrazi are an ancient race that once attempted to conquer the multiverse. Ages ago, they were locked away by three Planeswalkers on the world of Zendikar. Now, someone or something has weakened their prisons. The Planeswalker, Sorin Markov, one of the three that helped seal them away in the distant past, has returned to Zendikar in the hopes of resealing them. Nissa Revane, a young elf planeswalker who lives on Zendikar, aims to have them removed from Zendikar altogether, as she considers them far too dangerous to keep around.
According to Wizards of the Coast, the Eldrazi are native to the blind eternities, and have "Transcended Colors of Mana Altoghether".