In the Stronghold, a Dragon from Dragonspire may join a Hero battle as an Assist Dragon. Assist Dragons can accompany and reinforce a Hero team in all Map Stages and in Events or Quests that do not have competitive elements (Leaderboards). Players unlock the chance to use Assist Dragons once they receive their first Dragon. 

Dragons have Assist Skils, and when a Dragon accompanies a team into a battle, that Assist Skill acts as an additional Special Skill for their team. In addition to this, Assist Dragons also have a Spirit Bonus which boosts the Health, Attack, and Defense stats for the team they are assigned to.

A Dragon’s Assist Skill can be upgraded with the Assist Skill Parchments.