Katana Master

When you obtain this feat you gain 6 d10's of Ryu dice. Each stance requires a bonus action to start and end. you can have one stance active at a time. All dice are regained at the end of a short or long rest. 

Two Swords Under Heaven: 

This stance requires two weapons (one must be a katana). With both swords out, you press the advantage. While in this stance when you take the attack action you gain one more attack. As a reaction, if an attack were to hit you, you can expend a Ryu die and add that number to your AC to counter that attack. The AC bonus ends after that attack is resolved. You may also spend another ryu die to make a single attack and add the roll to your damage.

Power Strike: 

The first strike is the most important. When you take an attack action you can expend one ryu die to give yourself advantage. You can spend a second die increase the damage of your strike, roll both Ryu dice you used and add it to your damage roll. If you already have advantage you do not need to use two dice to gain damage bonus. 

Adaptive Technique: 

A warrior is always ready. Using a ryu die if your weapons are sheathed your first attack is taken with advantage. When prone, you may use a ryu die to stand without using any movement and make an attack. If you use a long or high jump, you may expend a ryu die to make an attack and roll it to add the damage to your attack. As a reaction you may use two ryu die to dodge an attack by going prone.