Blademaster

"You can only fight the way you practice"; words that form the core of the Blademaster's creed. No matter their origin, no matter their goals or aspirations, Blademasters are those who commit themselves to swordsmanship, and cast aside other forms of combat. Their blades move with finesse and grace unknown to lesser warriors, always managing to find that gap where the foes armour is weakest to deal a mortal blow. Theirs is no supernatural power, but simply superior strength of arms; utter mastery manifested in a single dynamic, devastating moment.

Several features of this subclass will refer to sword-type weapons. For these purposes, a sword-type weapon includes, but is not limited to; Dagger, Sickle, Shortsword, Greatsword, Longsword, Shortsword, Rapier, Scimitar, as well as any Magic Weapon that benefits from Proficiency with any of these weapons. A DM has final discretion on what is, or is not, considered a sword-type weapon for the purpose of this subclass.

Sword Savant

When you choose this archetype at 3rd level, you have taken the first steps to mastery of the blade, and the result are beginning to show. You may add a value equal to half your proficiency bonus (rounding up) to attack rolls made with sword-type weapons.  Furthermore, you gain proficiency in any weapon considered to be a sword-type weapon. However, you are no longer considered Proficient in weapons that are not sword-type weapons.

(N.B. Only the proficiencies granted by this feature are possible on D&D Beyond at the moment. Other aspects of the feature must be calculated manually.)

Slash Draw

Starting at 3rd level, you strive to ensure that your blade is always a threat, even when you are not holding one. On your turn as a bonus action, if you do not currently have a weapon equipped, you may select one sword-type weapon you are currently carrying and equip it; then you may make a melee attack against a creature within 5 feet of you. You may add either your STR Modifier or DEX Modifier to the result of the attack roll and damage roll for that attack, in addition to any other modifiers. 

You may only use this feature if you were not engaged at the beginning of your turn. 

Quicksilver Strike

Starting at 7th level, your swordsmanship is precision and speed incarnate, refined through practice. Practiced enough, a single, decisive blow can best any defence. When you declare the attack action on your turn with a sword-type weapon, you may choose to forgo a number of additional attacks granted by the Extra Attack Feature, up to a maximum of 3. For EACH attack forgone in this manner, apply the following:

• Add either your STR or DEX Modifier to the result of the attack roll, in addition to any other modifiers. 
• The attack deals 1d8 + your proficiency bonus in additional damage. The additional damage dice becomes a d10 at level 15. 
• Your Critical Range for that attack is increased by 1 (E.G Forgoing one additional attack in this manner would result in this attack scoring a critical hit on a result of 19-20. Two additional attacks forgone would result in the attack scoring a critical hit on a result of 18-20. Three additional attacks forgone would result in the attack scoring a critical hit on a result of 17-20).

Cut First, Cut Last

Starting at 10th level, your best defence is a good offence; a dead or wounded enemy can no longer threaten you. When a creature hits you with a melee attack, you can make a melee attack against them as a reaction. If your attack hits, you may reduce the damage you take from that attack by a value equal to your Fighter level, to a minimum of 0. 

Leaf Cutter

Starting at 15th level, your precision with a blade is terrifying to behold. You gain the following effects;

• You may add half your proficiency bonus, rounding up, to the damage of attacks with sword-type weapons.
• Your attacks with sword-type weapons increase their critical range by 1 (E.G They score a critical hit on a roll of 19-20).
• The damage dice for Quicksilver Strike become d10s.

Sword Saint

At 18th level, your blade flows like the wind, and cuts like water; relentless and rapid, a storm of steel. On your turn, as an action, you may make a melee attack with an equipped sword-type weapon. If the attack hits, you may make another attack as part of the same action, with a -2 penalty on the attack roll. Continue making attacks, increasing the penalty imposed by 2 each time, until an attack is missed.

Once you use this feature, you can’t use it again until you finish a short rest.