Studied the Blade

While others were drinking in the tavern, you studied the blade. You've learned to use balance and leverage to your advantage when wielding a longsword with two hands, letting the blade do the work. You gain the following benefits:

• Increase your Strength, Dexterity, or Intelligence score by 1 to a maximum of 20.
• When wielding a longsword with two hands, it possesses the finesse property for you.
• Before you make a two-handed melee attack with a longsword, you can choose to take a -3 penalty to the attack roll. If the attack hits, you add +6 to the attack's damage.
• When you are wielding a longsword with two hands and another creature hits you with a weapon attack, you can use your reaction to add half your proficiency bonus to your AC for that attack, potentially causing the attack to miss you.