Black Hacking done right |
Originally I was thinking along traditional HP lines, and having the highest HD of the two classes be the one the character used, in much the same manner gestalt characters in 3e take the best option. However, I want to Usage Die all the things, so let's do that with HP:
A character's health is represented by two Usage Dice (one from each Type), one of which is chosen to be the 'Flesh Wounds' die, the other becomes the 'Mortal Wounds die'. Whenever an attack penetrates the character's armor, make a Usage Die roll. On a 1 or 2 step the Usage Die down one die type as usual. If a player attempting to dodge rolls a critical failure, the Usage Die is automatically stepped down one.
If the Flesh Wounds die is a d4 and would be stepped down, that die is no longer used and the character is considered 'Bloodied'. Bloodied characters have disadvantage on all attribute checks. When the Mortal Wounds die is reduced below a d4, the character is OoA.
A character will likely have two different sizes of die, and it is up to the player to choose which will be Flesh/Mortal. It is probably best to make the larger die the Mortal Wounds die, though some players may wish to make a character that can take more Superficial Wounds before becoming Bloodied.
A short rest increments one HD up one step (a lost HD increments to a d4), a long rest increments two steps (these can be split between either Flesh/Mortal dice as desired).
'Backstab' needs adjusting now, but right now it will likely be an automatic crit against whichever HD the Assassin wishes to target.