Hearthstone's next expansion, Fractured In Alterac Valley, finally pits Alliance vs Horde. It's a way of bringing together all of the various mercenary characters that have been progressively built up over the course of the year, and part of that means new Hero cards based on each of the 10 characters. Among those is the Warrior Rokara.
Hero cards in Hearthstone are class Legendaries with big game-changing effects. They replace your Hero entirely, usually granting you a powerful Battlecry and significantly upgrading your Hero power. In the case of Rokara the Valorous, that means equipping a 5/2 Unstoppable Force, which smashes enemy minions into your opponent like croquet balls. Her upgraded hero power, Grand Slam, utilizes the new Honorable Kill keyword. It can always deal 2 damage, but if you do exact lethal to a minion, you'll also gain 4 Armor. That makes it a strong combination of offense and defense that can help you last into the late-game.
For those who have been paying attention to Hearthstone card reveals in advance of Alterac Valley, you may notice that Rokara's new 5/2 weapon is a mirror image of another legendary Hero card. The Paladin card Lightforged Cariel comes with her own weapon, a 2/5 weapon called The Immovable Object. So Rokara's Unstoppable Force pairs thematically with Cariel's Immovable Object. That's by design, as Blizzard intends the two to have something of a rivalry going into this final expansion: