I tried out the thief in a few example turns and the stealth system worked really well and I think unblockable damage makes a lot of sense thematically. Still even with the unblockable damage it's possible you will miss with both dice. But the question is if landing 2 unblockable hits is too much despite the set up conditions of having to be in stealth. Not sure. If you go with extra dice for backstab then I would say to still limit the thief to only a dagger/rapier/short sword as far as melee weapons go to really reflect the power of that backstab. Then if the thief backstabs he gets 2 additional dice. If you go this route then let the monster roll defense as well. That way the thief would really only engage in melee if he is backstabbing otherwise he should use a short bow or sling. That's how earlier editions of the thief would function anyways. When you get a chance try out some of these ideas and let me know what you think. Here's again a list of backstab options:
1. The current one I've listed where you would roll a maximum of 2
and any skulls would count as an unblockable hit.
2. Allow a single unblockable hit. No attack roll required.
3. Add additional dice to the attack. If using dagger add 2 additional
for a total of 3
. If using a short sword or rapier then the thief would roll a total of 4
. That might be a bit much. Anyways monster would roll for defense as usual. Personally I think only allowing the thief to backstab with a dagger is better thematically.
I personally like the 1st and 3rd option. 3rd is a bit weaker and therefore probably more balanced. So a thief using the 3rd option might look something like this:
Thief
Body
Mind
Attack
Defense
Move
Starting weapon: Dagger
Starting armor: None
Restrictions: Can not wear armor and can only use a dagger, short sword, rapier, sling, and short bow.
Abilities:
1. Starts with a toolkit
2. Stealth: If no enemies are in LoS at the start of your turn, you may use stealth but must roll one less movement die. If a monster appears in your LoS you must roll a die at the end of your movement for each monster that can 'see' you. If a black shield is rolled you are discovered, otherwise you remain undetected. While in stealth, you may only do free actions otherwise stealth is cancelled. The sole exception to this is searching for treasure. As long as monsters are in LoS you must continue to roll a die every turn at the end of your movement to maintain stealth even if you don't move. If you attack an adjacent monster from stealth, add an additional 2
to the roll against the monsters defense. Afterwards, regardless of outcome, you are detected.
3. When searching for treasure you may draw 2 cards and discard one. You may do this in the presence of enemies if you are in stealth.