Gambler

A young grinning man lays out his hand of cards, his voice like whiskey, mellow but backed with fire, "Four Emperors. I think thats my pot gentlemen. Lady luck is smilling on me today."  Right as his original hand of dwarves and dragons tumbles out of his sleeve and all hell breaks loose.

A wizend old gnome takes aim with his crossbow, talking to his companionsseated on the cart beside him. "Ayll bet ya ai caen shewt tha fancy haat uff tha there dwarves herd, tha wun ridun wit tham souldiors." His shot goes wide, richochets off a shield hanging from a warriors back, shoots straight up into the air, the sound catching everyones attention. With rapturous awe, everyone in the cart watches as the bolt comes down from the sky, through the dwarven mans hat, and into the backside of his horse. "TEWLD YA I CALD DU EET", AYM ON A STREK" the old gnome whoops and all hell breaks loose.

The assassin watches, unseen, from the balcony at the maelstrom of blades in the castle courtyard below. He knew that when all hell broke loose, that was his que, and lady luck was smiling on him today. He picked the lock on the window into his targets bedroom, sliding in unseen. He made a prayer to lady luck, betting his life on the lords faithful hound not hearing the sound of the window openning. The dogs ears barely twitched as he silently slid through the window. His knife finding clean and easy purchase in the lords back as his hand stiffled the cry. One attack was all it took, and the assassin fled into the night.

Gamblers take many forms, some find themselves in taverns and casinos around the continent. Others place their wagers on lifes simple things. But one thing remains true for all, when lady luck is smilling down on them, there is no more deadly enemy. Some gamblers live life on the edge, taking their luck as it comes. Others hone their craft and learn to read the signs so deftly, that they make their own luck.

Level 3: Hustler

When you take this subclass at 3rd level, you know most games, and how to cheat them. You gain proficiency in three games of your choice, as well as in Charisma (Deception) checks and Dexterity (Sleight of Hand) checks, if you don't already have them. When making an ability check to cheat at a game you are proficient in, you have advantage on the roll.

Level 3: Lady Lucks Fickle Favor

Starting at 3rd level, lady luck twists the world around you, but not always in your favour. Whenever you make a d20 test, a roll of an unmodified 1 always fails and an unmodified 20 always succeeds, irrespective of modifiers.

When you finish a long rest, roll a d20 and record the result. If the die shows a number between 2-10, you always fail on a roll of an unmodified 1 and the rolled number. If the die shows a number between 11-19, you always succeed on a roll of an unmodified 20 and the rolled number. The rolled number does not count as an unmodified 20 for the purpose of critical hits.

Level 3: Gambler's Stake

You have a stack of luck, represented by your Gambler's Stake Dice, which youre able to stake on any one wager. The Gambler's Stake Dice table shows the number of these dice you have when you reach certain Rogue levels, and the table shows the die size.

Gambler's Stake Dice

Rogue Level	Die Size	Number
3	D6	4
5	D8	6
9	D8	8
11	D10	8
13	D10	10
17	D12	12

 

You regain all of your expended Stake Dice when you finish a Long Rest.

Making a Wager. 

You place a bet on the likelihood of something happening. Whenever a creature you can see (inlcuding yourself) makes a d20 test, you may place a bet on the outcome. You may bet that the creature will succeed or fail on the roll. You must place a bet before any dice are rolled. You may bet a number of stake die up to your proficiency bonus, minimum of 1, on a single wager. You expend the Stake Die when you wager them. The results of the bet are determined when the DM declares the success or failure of the roll. Any effect (other than the Rouge's Stroke of Luck feature and the Boon of Fate Epic Boon) that allows a failure to be rerolled does not change the outcome of the bet. 

Success: If the wager succeeds you may roll the number of Stake Dice bet and deal the value rolled as psychic damage on your next successful attack. If you bet on you own attack roll, you may add the damage to this attack. Additionally, you regain half the expended Stake Die, rounded down.

Failure: If the wager fails, you roll the number of Stake Dice bet and take the value rolled as psychic damage. Self inflicted damge from this ability cannot be mitigated in any way. 

Level 9: Play the Odds

Starting at 9th level, you have learnt to twist luck every so often in your favor, and maybe bring some luck to another... good or bad... it depends, play the odds.

When you roll for Lady Luck's Fickle Favor you may roll twice and record both rolls. You may pick one for yourself, and as a bonus action, give the other to another creature of your choosing you can see. For 1 minute, the creature is affected by Lady Luck's Fickle Favor as if they were you, using the number you granted them. You may use this effect once per long rest. You regain a use of this feature whenever you suceed on a wager due to Lady Luck's Fickle Favor.

Level 13: Streak of Luck

By 13th level, you can snowball your luck. Not always for the best, but all bad streaks break eventually, and usually with a big break!

Streak of Good Luck. Whenever you suceed on two or more d20 tests in a row you become affected by the Bless spell until you fail on an attack roll, saving throw, or ability check. 
Streak of Bad Luck. Whenever you fail on two or more d20 tests in a row you become affected by the Bane spell until you succeed on an attack roll, saving throw, or ability check. 
Breaking a Bad Streak. Whenever you suceed on a d20 test while on a Streak of Bad Luck, your next attack is guaranteed to be a critical hit.

Level 17: Luck and Cunning

When you reach 17th level, you use your cunning and luck to bend the odds in your favor.

Whenever you succeed on an attack roll using Lady Luck's Fickle Favor, and deal sneak attack damage, you may use one additional cunning strike that costs 3d6 or less without forgoing the dice.

The following effects are now among your Cunning Strike options.

• Lucky Strike (Cost: 4d6). The target must succeed on a Constitution Saving throw, on a failure your sneak attack dice and any Stake Dice roll maximum damage.
• Misdirection (Cost: 2d6). The target must succeed on a Charisma Saving throw, on a failure the target has disadvantage on their next d20 test. If they fail on their next d20 test they take 1d12 psychic damage.
• Read the Odds (Cost: 1d6). Learn the targets AC, Spell Save DC, and any abilities or spells which allow them to modify these results (e.g. Shield spell, parry ability).