Duelist

One of the Rogue classes.

Hit Points
Hit Dice: 1d10 per level

Hit Points at 1st Level: 10 + CON modifier

Hit Points at Higher Levels: 1d10 + CON modifier per level

Proficiencies
Armour: Light armour, medium armour

Weapons: Simple weapons, hand crossbows, longswords, rapiers, shortswords

Tools: None

Saving Throws: Dexterity, Constitution

Skills: Choose two from Acrobatics, Animal Handling, Athletics, Lore, Insight, Intimidation, Perception, and Survival

Equipment
You start your adventure with the following equipment, in addition to the equipment granted by your background:
 * (a) a rapier, or (b) a shortsword
 * (a) a longsword, or (b) a shortsword
 * (a) a dungeoneer's pack, or (b) an explorer's pack
 * Studded leather armour, two daggers

Fighting Style
You adopt a particular style of fighting as your specialty. Choose one of the following options:
 * Duelling. When you are wielding a melee weapon in one hand and no other weapons, you gain a +2 bonus to damage rolls with that weapon.
 * Dual-Wielding. When you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack.

Features & Abilities

 * Combat Superiority (all levels). You learn manoeuvres that are fuelled by special dice called superiority dice.
 * Manoeuvres. You learn three manoeuvres of your choice, which are detailed below. Many manoeuvres enhance an attack in some way. You can only use one manoeuvre per attack.
 * Superiority Dice. You have four superiority dice, which are d8s. A superiority die is expended when you use it. You regain all of your superiority dice when you finish a short or long rest.
 * Saving Throws. Some of your manoeuvres require your target to make a saving throw to resist the manoeuvre's effects. The saving throw DC is calculated as follows: Manoeuvre save DC = 8 + your proficiency bonus + your DEX modifier
 * Action Surge (2nd level). You can push yourself beyond your normal limits for a moment. On your turn, you can take one additional action on top of your regular action and a possible bonus action. One you use this feature, you must finish a short or long rest before you can use it again.
 * Student of War (3rd level). You gain proficiency with one type of artisan's tools of your choice.
 * Combat Pragmatist (3rd level). You can use the action granted by your Action Surge to take the Use an Object action.
 * Ability Score Improvement (4th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Extra Attack (5th level). You can attack twice, instead of once, whenever you take the Attack action on your turn.
 * Ability Score Improvement (6th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Know Your Enemy (7th level). If you spend at least one minute observing or interacting with another creature outside combat, you can learn certain information about its capabilities compared to your own. The DM tells you if the creature is your equal, superior, or inferior in regard to two of the following characteristics of your choice:
 * Strength
 * Dexterity
 * Constitution
 * AC
 * Current HP
 * Level
 * Additional Manoeuvres (7th level). You learn two additional manoeuvres. You may also replace one of your existing manoeuvres with a different one.
 * Additional Superiority Die (7th level). You gain a fifth superiority die.
 * Ability Score Improvement (8th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Additional Manoeuvres (10th level). You learn two additional manoeuvres. You may also replace one of your existing manoeuvres with a different one.
 * Improved Combat Superiority (10th level). All your superiority dice turn into d10s.
 * Extra Attack (11th level). You can now attack three times, instead of twice, whenever you take the Attack action on your turn.
 * Ability Score Improvement (12th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Ability Score Improvement (14th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Relentless (15th level). When you roll initiative and have no superiority dice remaining, you regain 1 superiority die.
 * Additional Manoeuvres (15th level). You learn two additional manoeuvres. You may also replace one of your existing manoeuvres with a different one.
 * Additional Superiority Die (15th level). You gain a sixth superiority die.
 * Ability Score Improvement (16th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Second Action Surge (17th level). You can now use your Action Surge twice before resting, but only once on the same turn.
 * Quick Reflexes (17th level). You have become adept at laying ambushes and quickly escaping danger. You can take two turns during the first round of any combat. You take your first turn at your normal initiative and your second turn at your initiative minus 10. You can't use this feature when you are surprised.
 * Further Improved Combat Superiority (18th level). All your superiority dice turn into d12s.
 * Ability Score Improvement (19th level). You can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature.
 * Extra Attack (20th level). You can attack four times, instead of three times, whenever you take the Attack action on your turn.

Manoeuvres

 * Commander's Strike. When you take the Attack action on your turn, you can forgo one of your attacks and use a bonus action to direct one of your companions to strike. When you do so, choose a friendly creature who can see or hear you and expend one superiority die. That creature can immediately use its reaction to make one weapon attack, adding the superiority die to the attack's damage roll.
 * Disarming Attack. When you hit a creature with a weapon attack, you can expend one superiority die to attempt to disarm the target, forcing it to drop one item of your choice that it's holding. You add the superiority die to the attack's damage roll, and the target must make a Strength saving throw. On a failed save, it drops the object you choose. The object lands at its feet.
 * Distracting Strike. When you hit a creature with a weapon attack, you can expend one superiority die to distract the creature, giving your allies an opening. You add the superiority die to the attack's damage roll. The next attack roll against the target by an attacker other than you has advantage if the attack is made before the start of your next turn.
 * Evasive Footwork. When you move, you can expend one superiority die, rolling the die and adding the number rolled to your AC until you stop moving.
 * Feinting Attack. You can expend one superiority die and use a bonus action on your turn to feint, choosing one creature within 5 feet of you as your target. You have advantage on your next attack roll against that creature. If that attack hits, add the superiority die to the attack's damage roll.
 * Goading Attack. When you hit a creature with a weapon attack, you can expend one superiority die to attempt to goad the target into attacking you. You add the superiority die to the attack's damage roll, and the target must make a Wisdom saving throw. On a failed save, the target has disadvantage on all attack rolls against targets other than you until the end of your next turn.
 * Lunging Attack. When you make a melee weapon attack on your turn, you can expend one superiority die to increase your reach for that attack by 5 feet. If you hit, you add the superiority die to the attack's damage roll.
 * Manoeuvring Attack. When you hit a creature with a weapon attack, you can expend one superiority die to manoeuvre one of your comrades into a more advantageous position. You add the superiority die to the attack's damage roll, and choose a friendly creature who can see or hear you. That creature can use its reaction to move up to half its speed without provoking opportunity attacks from the target of your attack.
 * Menacing Attack. When you hit a creature with a weapon attack, you can expend one superiority die to attempt to frighten the target. You add the superiority die to the attack's damage roll, and the target must make a Wisdom saving throw. On a failed save, it is frightened of you until the end of your next turn.
 * Parry. When another creature hits you with a melee attack, you can use your reaction and expend one superiority die to reduce the damage by the number you roll on your superiority die + your Dexterity modifier.
 * Precision Attack. When you make a weapon attack roll against a creature, you can expend one superiority die to add it to the roll. You can use the manoeuvre before or after making the attack roll, but before any effects of the attack are applied.
 * Pushing Attack. When you hit a creature with a weapon attack, you can expend one superiority die to attempt to drive the target back. You add the superiority die to the attack's damage roll, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you push the target up to 15 feet away from you.
 * Rally. On your turn, you can use a bonus action and expend one superiority die to bolster the reserve of one of your companions. When you do so, choose a friendly creature who can see or hear you. That creature gains temporary hit points equal to the superiority die roll + your Charisma modifier.
 * Riposte. When a creature misses you with a melee attack, you can use your reaction and expend one superiority die to make a melee weapon attack against the creature. if you hit, you add the superiority die to the attack's damage roll.
 * Sweeping Attack. When you hit a creature with a melee weapon attack, you can expend one superiority die to attempt to damage another creature with the same attack. Choose another creature within 5 feet of the original target and within your reach. If the original attack roll would hit the second creature, it takes damage equal to the number you roll on your superiority die. The damage is of the same type dealt by the original attack.
 * Trip Attack. When you hit a creature with a weapon attack, you can expend one superiority die to attempt to knock the target down. You add the superiority die to the attack's damage roll, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you knock the target prone.

Meta Notes
Vanilla Fighter class with Duelist subclass, plus some from Rogue (Thief) class.