It appears Valeera Sanguinar the blood elf is making her way into Heroes of the Storm.
— Heroes of the Storm (@BlizzHeroes) January 13, 2017
Valeera Sanguinar is an NPC in World of Warcraft, and is not aligned with either Horde or Alliance. Her loyalties lie with her friends and own ideals.
In Hearthstone, she is a Rogue class who was added to help balance faction, race and gender representation.
Also, in case you forgot, its a free hero weekend for anyone who wishes to play Heroes of the Storm.
The Free Hero Weekend ends on January 17.