From Dragon Mania Legends (DML) Wiki
Elementː Wind I think all elements should have mastered skills so level 7 since level 6 is the highest and max i suppose there should be a extra skil to make the game so impressive and more better.
Mastery Skill Level 6
Last Breathː Reduces the damage from your enemy depending on your dragon's level is how much damage the reduction attack does and lasts for 4 turns on 1 enemy
Storm's a Brewin is to reduce the damage from all enemies the attacked ones gets reduced more and the rest is by less damage but all lasts for 2 turns.
New ones for level 7 2 on top of 1 like like last time with 6 but this time with multiple
Stratocumulus Cloudsː Reduces Target's Damage by the amount of it's level power and Lasts for 6 turns (can't be removed by Restorative Recourse) ( But the other mastered skill can expunge it)
Storm's Cursing Speedː Hits all Enemies 50 percent chance to block the opponent's damage (Lasts for 1 Turn)( This way it can't attack it's turn is automatically skipped) and a 5 percent chance for the rest of the enemies to deal no damage for 2 turns ( And if somehow does not have a special effect for the chances then it regularly reduces only damage ( Depending on your Dragon's Power Level )