Duelist

You are a master of single combat, deadly with a blade in hand. You honed your skills with a trainer or through experience, becoming a force to be reckoned with. While the flashy magics and fancy moves of other adventurers are all well and good, when it comes down to brass tacks, there aren't many people who can stab or slice an opponent better than you.

Duelists might be gladiators or mercenaries that prefer a more elegant approach to fighting, nobles who were taught the sword from a young age, someone who places honorable duels in high regard, or just an adventurer with a penchant for single combat.

Duelist DC: 8 + proficiency bonus + Dexterity modifier

Opportunist

At 3rd level, when you are wielding a weapon you a proficient with and a creature within 5 feet of you misses you with an attack or attacks a creature other than you, you may spend a reaction to make an attack against that creature with that weapon, and you have an additional bonus to attack and damage rolls for that attack equal to your proficiency bonus. You may use this feature a number of times per short rest equal to your proficiency bonus.

Additionally, you gain advantage on all Opportunity Attacks made with a melee weapon you are proficient with.

Master of Body

At 3rd level, you gain advantage on Dexterity saving throws to avoid traps and nonmagical effects that you can see, and you gain a bonus to your initiative equal to your proficiency modifier.

Duelist's Flourish

At 7th level, when you miss an attack, you can use a bonus action to attempt to disarm your target. The target must make a Dexterity saving throw against your Duelist DC. On a failure, their weapon is ripped from their hand and thrown 10 feet away in a random direction.

If the target fails their save, you may immediately, as a free action, make an attack against them, adding your proficiency bonus to the attack and damage rolls for that attack.

Tempo of Battle

At 10th level, whenever you use your Opportunist feature, you gain a bonus to your AC equal to your proficiency bonus until the start of your next turn.

Also at 10th level, whenever you use your Duelist's Flourish feature, you gain advantage on your next attack roll against the target.

Sharpened Mind

At 15th level, you gain advantage on all Wisdom, Charisma, and Intelligence saving throws made while in combat. Additionally, whenever you use your Duelist's Flourish feature and the target fails the save, you gain temporary hit points equal to twice your proficiency modifier.

Foregone Conclusion

At 18th level, your attacks score a critical hit on a roll of 19 or 20.

Additionally, whenever you hit a creature with an attack that does not score a critical hit, your threshold to score one is lowered by one. This effect cannot lower your critical hit threshold below 15. This effect ends if you are incapacitated, score a critical hit, attack a different creature, or combat ends.