Two-Hander Extraordinaire

You master the use of Two-Handed weapons, gaining the following benefits:

• You gain proficiency with Two-Handed weapons.
• You can fight with a Two-Handed weapon while wielding it in one hand, suffering a - 2 penalty to attack and damage rolls made while doing so.
• When wielding a Two-Handed weapon with both hands you may also equip a shield, however the bonus it provides to your AC is halved.
• At the start of your turn, while wielding a Two-Handed weapon with both hands you can increase the size of that weapon's damage die or dice by 1. The effect lasts until you make your first successful attack with this weapon or switch to holding it in one hand. You can use this ability a number of times equal to your Proficiency bonus - 1. You can use this ability multiple times on a single turn. When you finish a short or long rest, you regain all expended uses and any effected dice return to their normal size.