twitch.tv/SprinkleBeard
Dragon has a big breath attack that can be interrupted by depleting his purple health bar. Things like Poison or HP burn can help take a big chunk out of this bar. His breath can stun, and his other aoe attacks can weaken and poison your team, so having a way to stay healthy is very important. Healing, cleanses, or Block Debuffs can be a big help, as well as the usual Def Up for your team and the Attack Down for theirs!