Purple dragon knights are warlords, tyrants. You despise these conquerors and desire nothing more than to tair down the system and turn society into a game of survival. 

Know the enemy

If you didn’t possess it already then you gain monstrosities as an additional favoured enemy.

Disarming strike

When you hit a target with a melee attack (and later a ranged attack at level 14) your target must roll a dexterity saving throw (DC= 8+proficiency+ dexterity modifier). If they fail the saving throw then they drop whatever they were holding. On a success nothing happens. 

Instant karma

Upon striking a target they must make a wisdom saving throw or be magically restrained by the elements around it (vines, extended grass, etc.). They must make a strength saving throw (DC=13) to escape said grapple. 

Aim to kill

By 15th level you have become a master of your craft. A true purple dragon slayer. You can now expend a fourth level spell slot to instantly kill any enemy if they either have 10% of their health left. 

No sight required

You grave advantage on any non sight based perception checks