Mastered One-Handed Training (Greatsword)

With extensive training, you have mastered how to effectively use your body to balance the weight of a Greatsword. You gain the following benefits:

• Your Strength score by 1, to a maximum of 20. 
• Your Dexterity score by 1, to a maximum of 20
• You gain Proficiency with Greatswords
• You can use Greatswords as if they were a one-handed weapon. When you are wielding a Greatsword as one-handed weapon, the value of the damage dice of that weapon is reduced by -2 (Greatsword (2d6) would deal 2d4 of damage.)
• You can also use shields or dual-wield it with a weapon that have the light or medium propriety.