Due to your continual practice, training, and dedication to a weapon, you have become an expert in it's use.

You choose one weapon you are proficient with when you take this feat and gain the following general benefits:

-If it is a martial melee weapon, you gain +1 to your choice of Strength or Dexterity.

-You gain expertise with the weapon, adding double your proficiency to your attack rolls.

-When you use the Attack action and attack with a longsword, you can use a bonus action to make two additional attacks with another weapon in your other hand instead of one. You don't add your ability modifier to the damage of the bonus attacks, unless that modifier is negative, or you have the two weapon fighting style.

In addition to these bonus', you gain the ability to make specific actions with it that are specific to this weapon. You can take this feat again choosing a separate weapon.

Defensive Stance- You can use your reaction to enter a defensive stance, gaining +1 to AC until the start of your next turn.
Retaliatory strike- On your turn, you can use your reaction to raise your sword in preparation for an attack. Until your next turn, the first time you are hit by a creature, you make an attack with your Longsword.

If you continue to train for an additional 180 days with this weapon, you gain the additional action:

Retaliatory Stance- On your turn, when you use the retaliatory strike action, you instead make an attack with your Longsword each time you are attacked.