Odium

Odium is a Shard, widely speculated to be held by Rayse. The word Odium is defined as "an intense hatred or dislike," which certainly seems to fit with what we've seen of Rayse so far.

Odium has as of yet been mentioned only in The Stormlight Archive, and based on Dalinar's vision of The Almighty at the end of The Way of Kings, it seems likely that Odium will become the primary antagonist of the series. The Almighty declares that he was killed by Odium. He also implies that Odium is the cause of the Last Desolation, and if not the leader of the Voidbringers, then at least allied with them.