Dragons are ferocious allies to have in combat.
Even young dragons can be sent out to attack creatures found throughout Westeros. However, even as your dragon gets larger, they cannot be sent on marches alone. Dragons always require troops on the ground to accompany them, so pair your troops wisely in order to stack on bonuses provided by the talents you've selected.
The only times your dragon cannot be sent on a march, are when it has a timer running during an upgrade, or when its incapacitated from its injuries. Your dragon can become incapacitated after its health falls to zero. Once incapacitated, it will instantly return to the Dragon Pit in order to rest and heal. It cannot act again until its reached full health. Your dragon's health restores slowly over time, but this can be sped up with gold.
As your dragon grows, you can research new and better combat abilities. In time, your dragon can learn to help gather resources, attack other keeps, and in the future, your dragon will have the option to attack Seats of Power.
When your dragon is out on a march, it will no longer display within the Dragon Pit. As such, it cannot defend your keep, nor provide defensive bonuses gained from its presence.
When your dragon reaches its target, it will attack before the other troops accompanying it. This guarantees the most damage to your enemies and helps minimize injuries inflicted on your troops.
While your dragon technically functions as a troop, it is not categorized as one. Therefore, any bonuses provided to "troops" will not count for your dragon. Dragons have separate bonuses they can earn through research, talents selected, and other areas of the game.
Some combat stats apply specifically to your dragon. Other stats are bonuses granted BY your dragon to other sources (such as boosts to other troops). View your Dragon Stats for more information on your dragon's current power and abilities. Your dragon will also have their info displayed in battle reports.
When scouting your enemies for dragons, you will only be able to see they have a dragon once your watchtower is high enough level to see exact troop levels. You then will see the dragon and its level only if it is available for combat (e.g. not upgrading, incapacitated, or away).
Repel Strike is an ability used when your dragon is defending. This ability will harm incoming enemy troops; damaging them before they can attack. The damage amount for this ability depends on multiple factors - your dragon’s level, talents you've selected, research, and more.
Repel Strike must be researched at your Maester’s Tower before it can be used.
A dragon’s Tenacity functions similarly to stamina when using a dragon’s ability. At this time, Tenacity is only consumed when a dragon uses Repel Strike. Once Repel Strike has been used, some of your dragon’s Tenacity will be depleted. Tenacity can only be replenished by using the “charge” button. Once a dragon’s Tenacity has been charged, a cooldown timer will start before you can charge it again. You can also pay gold to reduce the timer immediately.
The Tenacity bar will not display until Repel Strike has been researched.