So instead of calling it Expertise, Skill, Martial Damage Dice, etc..
Let's call it power dice.
If a fighting class has the Parry maneuver, he rolls power-die+str mod when reducing damage with his strength based weapon.
Or the fighter can spend his 1 die on Deadly Strike and do power die+str mod extra damage.
If a caster uses an abjuration spell or a movement spell such as "Levitate" as a defensive reaction, she can reduce her damage by her power die+int mod.
If a cleric is healing an ally as a reaction, he can heal power die+wis mod.
| Level |
Power Die |
Or +/- |
| 1-5 |
1d4 |
2 |
| 6-10 |
1d6 |
3 |
| 11-15 |
1d8 |
4 |
| 16-20 |
1d10 |
5 |
| 21-25 |
1d12 |
6 |
