Thursday, February 6, 2014

Reaction-Roll Stealth

So far, the skill-based stealth system I've been using has been difficult to run without a battlemat, while the default "X on 1d6 to surprise" system still strikes me as pithy and undramatic (except in the simple case of encounters). But the reaction roll, which I've been using extensively through On the Non-Player Character, fits the bill perfectly - instead of binary success/failure, you get piling bonuses which slowly push you towards success or failure. Additionally, this is consistent with the current systemic division I'm contemplating - using d20s for the combat system, 2d6 for noncombat rolls, and dice pools for anything to do with magic. The following stealth system is mostly inspired by On the Non-Player character, and a bit from this Google+ discussion.

Stealth actions are resolved in segments of one minute, rolling 2d6 (plus Dex mod) each time. Bonuses are persistent, and cumulative. Consult the following table:

2Found or -4You're surprised!
3 - 5-2No surprise
6 - 80You surprise!
9 - 11+2Ranged backstab!
12+4 or HiddenMelee backstab!

Sneaking is used for any actions you take while undetected. The following bonuses apply:

No movement or other actions (hiding): +4
Combining two actions (moving twice, moving while tracking, etc.) -4 per action
Trickster/thief/etc. +level
Distance: +1 per 100' from nearest sentry/enemy, -1 per 10' closer than 100'
Terrain/weather/etc.: +2 or -2 depending on conditions

Found means that stealth ends (for you) and you're detected. Start encounter as normal - stealth can no longer be used. You can, of course, try to hide again - you can roll on the Sneak table instead of taking another action each round, with cumulative bonuses. Stealth starts again once you get Hidden.

Backstabbing is what you roll when you're trying to end stealth and initiate combat. On a 2, you totally bungle it, and your opponent gets to act against you in the surprise round, while on a 6 or higher, you surprise them, getting a free round. On a 9 or higher, you've spent enough time observing and positioning yourself to get a sweet sniper shot on an opponent, gaining a +4 to hit. On a 12, you're close enough to do it with a melee weapon, and can precisely target weak points or chinks in your opponent's armor - you get a +4 bonus to hit, and deal double damage.

Backstab bonuses:
Multiple actions (opening a door and then backstabbing, for example): -4 per action
Trickster/thief/etc.: +level
Distance: -1 per 100' from target, +1 per 10' closer than 100'
Terrain/weather/etc.: +2 or -2 depending on conditions