How do you get Dawnseeker in Game of Thrones: Dragonfire?

Dawnseeker is the game's pre-registration reward.

It's a Rare Sentinel, key stat Initiative (56), with a green affinity for Spearmen. Its Order, Radiant Wings, boosts the team's Instinct and Initiative (+20%, 30% chance), hits in tactical damage and heals 2 allies.

It's a solid free support dragon to start with: its set habit Sunbreak pushes the tactical damage of its Order (+100%), and First Light grants First-Strike to allies. Perfect in a Spearmen army, given its green affinity.