Fighter Archetype
Blademaster
The archetypal blademaster focuses all their combat training on the masterful art of gliding around the battlefield with a single blade in hand. In single combat, they have no equals, and even in pitched battle managing to land a blow on a blademaster is no easy task.
Lone Sword Dueling
Starting at 3rd level, while wielding a melee weapon in one hand and nothing in the other, you count as Lone Sword Dueling. While Lone Sword Dueling, you gain a +1 bonus to AC and +1 to attack rolls you make with your wielded weapon. You also gain the ability to use versatile weapons in one hand during combat, and in two hands when attacking. This gives you bonuses due to having a weapon in only one hand as well as bonus damage die from wielding a versatile weapon with two hands. In addition, when Lone Sword Dueling, the weapon you're wielding gains finesse.
Combat Stances
Starting at 7th level, you are able to choose between a number of combat stances to have activated while you are Lone Sword Dueling. Only one can be active at any time. At the start of each turn you decide what combat stance you will have active. The possible stances are listed below.
Closing
Your speed increases by 10 ft, and you ignore difficult terrain.
Dodging
You gain a +2 bonus to AC while Lone Sword Dueling.
Dueling
You gain a +2 bonus to damage dealt by your wielded weapon while Lone Sword Dueling.
Sweeping
At the cost of a -2 penalty to attack rolls made with and damage dealt by your wielded weapon, attacks you make this turn with your wielded weapon will target everyone within its range.
Blade Dancing
Starting at 10th level, Enemies have disadvantage on all attack rolls against you. However, your maximum hit points and hit die are halved, as well as the number of hit points your gain upon leveling up. Your speed while in combat also increases by 20 ft.
Elusive
Starting at 15th level, once per round of combat you may cause someone targeting you with an opportunity attack to automatically fail the attack roll. You also have resistance to all damage from opportunity attacks.
Eyes of Steel
Starting at 18th level, you gain a bonus to attack rolls made with your wielded weapon while Lone Sword Dueling equal to your proficiency bonus.