When I come into play, discard a card or you must eliminate me. At the start of each round, put all Ice Creature cards from your discard pile into play in my zone.
Ymir: Frost Giant dominates any combat he enters. But that's not all! You can use Titans like Derenzar: Unruly Titan and Ferric Warbringer: Spiked Warrior to fill your discard pile with Ice Creatures. Then, at the beginning of each round, Ymir will bring them to the Mission map! That makes it really easy to pay for Exhaust Actions, plus the Ice Creatures will provide some extra firepower. When they go down, they'll even stun heroes that would threaten their master! Discard Gawain: Forest Warrior when Ymir comes into play, and you'll get to ready a hero, too.