Quick Build
To quickly create a Thief, follow these suggestions. First put your highest ability score in Dexterity followed by Constitution. Second choose Mink as your species.
HIT POINTS
Hit Dice: 1d8 per Thief level
Hit Points at 1st Level and beyond: 8 + your constitution modifier
Energy POINTS
Energy Dice: 1d10 per Thief level
Energy Points at 1st Level: 10 + your Constitution modifier
Energy Points at Higher Levels: 10 + your Constitution modifier per Thief level after 1st
PROFICIENCIES
Armor: Light Armor, Simple Clothing, Fine Clothing, Luxury Clothing
Weapons: Simple Weapons, Simple Firearm Weapons, Martial Firearm Weapons
Tools: Lockpicking, Disguise, Weaponsmith's, or Botanist's
Saving Throws: DEX WIS, INT
Skills:
Stealth, Choose four others of your choice
Technique Abilities
Brawl
Brawl Save DC = 8 + your proficiency bonus + your Strength modifier
Brawl Attack Bonus = your proficiency bonus + your Strength modifier
Special
Special Save DC = 8 + your proficiency bonus + your Intelligence modifier
Special Attack Bonus = your proficiency bonus + your Intelligence modifier
Agile Strikes
You are able to deftly aim your attacks. At 1st, You are able to use Dexterity instead of Strength for Brawl Technique Save DC and Attack calculations.
Quick Feet
Your calculated and deft movements give you an edge on the roughest of battlefields. Also at 1st level you ignore difficult terrain. Additionally, you can choose one of the following bonuses, your choice cannot be changed later.
You add your full proficiency bonus instead of half proficiency bonus to initiative rolls
You gain a climbing speed equal to your highest movement speed.
Your walking speed is increased by 10ft.
Pinpoint Strike
You are able to spot openings in an enemies defenses allowing you to hit them where it hurts most. Beginning at level 1, once per turn, you can deal an extra 1d8 damage to one creature you hit with an attack if you have advantage on the attack roll or if an allied creature, that isnt incapacitated, is within 5 feet of it, and you don’t have disadvantage on the attack roll. The amount of extra damage increases as you gain levels in this class as shown in the class table.
Cunning Action
You are able to see the environment and take advantage of it in ways most others cant. At 2nd level, As a bonus action on your turn you can take the dash, disengage, or hide action as a bonus action on your turn. Additionally you can move your move your full movement speed while stealthing and hiding.
Thieves Mark
You know the ways of picking out a mark and seeing their weaknesses as well as their strengths. Also at 2nd level at the start of each round choose a combatant you can see. You may learn one of the following aspects of your choice about your chosen mark:
Any elemental affinities they have.
If they’re a devil fruit user. You also learn the category of devil fruit (Paramecia, Zoan, Logia), but not its effects
Damage resistances the target has
Damage Immunities the target has
Damage Vulnerabilities the target has
Condition Immunities the target has
Additionally, you gain +1 to attack rolls against your mark and for each consecutive round you focus on the same target you gain +1 to your attack rolls to a maximum of +3. This bonus resets to 0 if you would change to a different target.
Thieves Method
You’ve developed your own way of thievery. Your method grants you additional features at levels 3,7, 10,14,17.
Ability Score Improvement
When you reach 4th and again at 8th, 12th, 16th, and 19th, level, you can increase one ability score by +1 & a Feat of your choice that they qualify for. As normal you can’t increase an ability score above 20 using this feature
Uncanny Dodge
Starting at 5th level, when a creature that you can see would deal damage to you, you can use your reaction to halve the triggering attack’s, technique’s or effect’s damage against you. (edited)
Expertise
Also at 5th level, choose any one skill or tool kit that you have proficiency in. You gain expertise in the chosen skill or tool kit instead. When you would reach 15th level, you can select one more proficiency (in skills or tools) to gain this benefit.
Rogue’s Ploy
You’re always scheming and plotting new ways and methods for your next big score. At 6th level you’ve developed your big ploy to turn the tide in your favor in any given situation choose from the listed ploys at the end of the class. At 11th level you may choose another.
Activated Trap Card
You've been watching your target and know their tricks. When the target of your Thieves Mark would take a reaction against one of your actions you make make a weapon attack against them as a free action.
The Ole Switcharoo
You've developed a method of fooling opponents to thinking they have a target in their sights only to replace it with another. As a Bonus Action on your turn you may swap places with an allied creature within 15 ft of you. Once you this twice you must finish a rest before you can do so again.
I'll Take Some Too
Your not one to just sit back while others take a swig and you'll snatch the bottle out of their hand if need be. When a creature your adjacent to receives healing or temporary hit points roll a Slight of Hand check you may reduce the amount they receive by half of your check (rounded down) and you receive that amount instead.
Pocket Sand
You know how to hide even when there isn't any cover to be found. Twice per rest you may do one of the following, reroll a hide check taking the higher of either roll, or hide from the target of your Thieves Mark even if there isn't anything to obscure you.
Method Acting
You prefer to get real with your acting. When you roll a Performance or Deception check you can choose to gain a 1d4 bonus to the roll after you know its result. If this would change a failure to a success you cannot use this again until you finish a rest.
Parkour Parkour
You know how to get out of tricky spots. When you would make a Dexterity Saving throw you can move half of your movement speed as a reaction. If this would cause you be out of the range attack, effect, or technique it is treated as a successful save. Once you have used this you can't use it again until you finish a Long Rest.
Advanced Preparations
A thief is always ready for some sort of trouble and has prepared for their schemes to go south quickly. At 9th level choose one of the following benefits, at level 15 choose another.
Tricky Maneuvering: Attacks of opportunity against you are always made at disadvantage.
Evasion: When you are subjected to an effect, that allows you to make a Dexterity saving throw to take only half damage, you instead take no damage if you succeed on a saving throw, and only half damage if you fail.
Prepared Strike: When you are hit by a creature's attack. The next time you deal damage to that creature you can Pinpoint Strike regardless of circumstance.
Know Your Weakness: Choose between Physical, Mental, or Elemental Status Conditions. You gain a 1d4 bonus when making a save against a Status Condition of that category. This can be chosen twice choosing a different category each time.
Stolen Move: You know how to steal just about anything even some additional actions. At 13th level once per Short Rest at half you initiative count you can choose to use either a Bonus Action or Movement action.
Double Marked
At 18th level you've learned to keep an eye on multiple enemies at once. You can use your Thieves Mark feature on two separate creatures. Additionally choose Techniques or Weapon attacks when your mark reaches its maximum bonus your crit range for the chosen type is increased by +2. This choice cannot be changed later.
Finisher
At 20th level you've learned to steal kills as well as everything else in sight. Once per Short Rest when a creature under your Thieves Mark is below 50% Hit Points you may choose to change a normal hit into a Critical Strike.