Longsword Master

You’ve extensively trained yourself in the use of longswords, both in the one-handed and two-handed styles. You gain the following benefits:

• You gain access to special stances that you may swap to as a bonus action, these stances are always active as long as you are not incapacitated and are wielding a longsword, Additionally the stance you start combat with is always the last stance selected.
• Offensive Stance: You gain a +1 bonus to your Attack and Damage rolls when wielding a longsword.
• Defensive Stance: You gain a +1 bonus to your AC and dexterity saving throw modifier when wielding a longsword.
• When you use a longsword, its damage die changes from a d8 to a d10, and from a d10 to a d12 when wielded with two hands.
• When you hit a Large or medium creature that's wielding a weapon, you can attempt to knock the weapon from its hand as a Bonus Action. Make a resisted Strength (Athletics) check. If you win, you disarm that creature and can make an attack against that creature using your reaction, causing additional damage equal to your longsword damage die on a hit.
• When you make an attack with a longsword with Advantage, your attack ignores resistances to slashing damage.