Arthur Dayne

Sword of the Morning: This creature cannot be persuaded or intimidated.

Dawn. Melee Weapon Attack: +10 to hit, reach 6 ft., one target. Hit: 17 (2d12 + 5) slashing damage. 

Disarming attack. When you hit a creature with a weapon attack, you can expend one superiority die to attempt to disarm the target, forcing it to drop one item of your choice that it's holding. You add the superiority die to the attack's damage roll, and the target must make a Strength saving throw. On a failed save, it drops the object you choose. The object lands at its feet.

Pommel strike. Strike someone with the pommel of your sword, doing 1d6 damage if it hits.

Parry. When another creature damages you with a melee attack, you can use your reaction and expend one superiority die to reduce the damage by the number you roll on your superiority die + your Dexterity modifier.

Arthur Dayne's Superiority die is a d12.  He has 6 dies.

Riposte. When a creature misses you with a melee attack, you can use your reaction and expend one superiority die to make a melee weapon attack against the creature. If you hit, you add the superiority die to the attack's damage roll.

Last stand (Costs 1 Actions). When Arthur Dayne reaches below half of his hit points he can boost his AC by 2 until end of combat.

For the Prince (Costs 1 action). Gains advantage on Attack Rolls until end of combat.

Arthur Dayne has two legendary actions.

Enter the description for how mythic actions work for your monster here.

Mythic Action Name (Costs # Actions). Enter the description for your mythic action.