The gambling addict(finished version)

gambler rogues love the thrill of risking it all to hit a jackpot, (don't feel like making flavor text)

Gamblers die

at 3rd level whenever you roll a d20, before rolling you may substitute your die with the gambler die, the gambler die is like a d20 but rolling a 2,3,4,5,6,7 or 8 counts as a nat 1(automatic fail)and rolling a 14,15,16,17,18 or 19 counts as a nat 20(automatic success), also teammates within 60ft of you may use a bonus action to substitute their die roll with the gambler die if you are willing. 

the gambler dice is unaffected by advantage/disadvantage or any ability that makes you reroll your dice, it is also unaffected by reliable talent or an ability that forces a die roll to be a number (like portent or eloquence bard). it does work with guidance or ability scores if you do not roll a nat 1 or nat 20.

you can use this ability a number of times equal to 1 + your proficiency modifier, uses reset upon taking a short or long rest

The house always win

at 3rd level whenever you roll a nat 20, the next d20 you roll(not including the gambler die) will roll with disadvantage 

additionally rolling a 2,3 or 4 on sneak attack damage counts as a 1 if you have rolled a nat 20 before on an attack roll, this effect resets upon a long rest .

 

Jackpot

 at 3rd level sneak attack deals an extra 1d6 damage when you roll a nat 20 plus an extra 1d6 at 4th(2d6),8th(3d6),16th(4d6) and 20th(5d6) level

rolling a nat 20 on an attack roll allows you to use your sneak attack.

Addict

at 7th level when rolling the gambler die if you roll a nat 20, you may roll the gambler die again next turn without expending a charge of the gambler die

Dopamine rush

at 13th level you may do anything that takes 1 action and uses a d20 as a bonus action if you roll with the gamblers die

the compulsive thrill you get from risking it all has heightened your senses, causing you to move faster than usual

Last gamble

at 17th level when you are reduced to 0 HP you may roll with the gambler die, if you roll a nat 20 you stay alive with 1 HP, if you roll a nat 1 you get two failed death saves, if neither nothing happens

the thrill is keeping you alive. you can't live without it now.

Point of no return

at 20th level every d20 roll is a gambler dice and numbers 1-9 count as a nat 1 and numbers 10-20 count as a nat 20.

what have you to gain?, you are nothing without gambling, it has become apart of you. Are you happy? Are you powerful? What about your loved ones? Are they happy with this?. you should have stopped but you didn't.why didn't you stop?, you have no one to blame but yourself at this point. Goodbye.