[Mod Request] Rogue Subclass: Dagger Master (focus on using a single dagger)

[Heafoxyz]

Hey, community!

I am looking for someone to create a subclass for a rogue that focuses on using a single dagger, without any complicated mechanics.
I would appreciate any response! 
If you have any questions just ask me here or in discord: heafoxyz

Before we begin, let me explain why there are so many passives: Dagger Master uses only one dagger and therefore does not have the ability to use off-hand attacks or gain the benefits of off-hand weapons.

(P) – Passive; (A) – Active; (R) – Reaction

Rogue subclass: Dagger Master

Dagger Masters are rogues who prefer a reliable dagger to other weapons. They always achieve their goals by any means, whether it's an open duel or a sneaky attack from the shadows.

Level 3:
Dagger Master: Relentless Strikes (P)
While your off-hand is empty, attacks with a Dagger deal 1d8 damage, unless it's normal damage is higher.

Dagger Master: Lethality (P)
While your off-hand is empty, a Critical Hit with Dagger deals an additional 2 damage.
At Rogue Level 6, the damage increases to 4 
At Rogue Level 9, the damage increases to 6
At Rogue Level 12, the damage increases to 8

Dagger Master: Turn the Tables (P)
If your hit points are at 50% or fewer and you do not use Sneak Attack during your turn, you will gain Advantage on all melee attack with a Dagger until the end of your next turn.

Dagger Master: Bonus Attack (P)
After making an attack with a Dagger, you can make another attack with that weapon as a Bonus action.

Dagger Master: Bonus Attack (A)
As a Bonus action, make a melee attack with your weapon.

Level 9:
Dagger Master: Improved Critical Hit
While your off-hand is empty, the number you need to Roll a Critical Hit while attacking with a Dagger is reduced by 1. This effect can stack.

Sneaky Riposte (R)
When a creature misses you with a melee attack, you may riposte, inflicting Sneak Attack damage if you have advantage.

Edited March 19 by Heafoxyz

[Heafoxyz]

Updated first post.

For modders: I will show you associated abilities.

Off-hand mechanics can be taken from Duellist's Prerogative.

Dagger Master: Relentless Strikes (P) is Monk's Martial Arts: Deft Strikes but now scaling and working only with a dagger.

Dagger Master: Lethality (P) is Dolor Amurus passive, but scaling with level.

Dagger Master: Turn the Tables (P) is unique passive, I can't find any same abilities. But it should be kinda easy: if hp <= 50% and Sneak Attack > 0 then gain Turn the Tables buff for 1 turn.

Dagger Master: Bonus Attack (P) both passive and active parts can be taken from Polearm Master or Great Weapon Master with some adjustments.

Dagger Master: Improved Critical Hit (P) is Duellist's Prerogative passive but for dagger.

Sneaky Riposte (R) is already existing Sneaky Riposte ability used by Lady Ague and Lady Quinsy.

Edited March 19 by Heafoxyz