If one group is ambushing the other, the ambushing group gets a surprise round.
Initiative is your DEX plus any modifiers from abilities and items. You don't roll. If there's a tie, the creature with the highest Dexterity goes first; if there's another tie then the GM decides.
On Your Turn
Can attack and move, or do something else and move.
Can't move and cast a spell or use a spell-like ability at the same time. You may be able to attack and cast as a Stunt at the GM's discretion.
To hit, roll under 10+STR (melee) or 10+DEX (ranged). Add enemy AC to your attack roll. On a miss, you still deal half damage, but subtract enemy armor from the damage you deal.
You can Stunt on your attack and do something extra, like making a called shot, tripping, sundering a shield, disarming, or pushing, by risking dealing no damage on a miss at all. Tell the GM you're doing this and what in specific you want to do on a hit before you attack.
If you're dual-wielding, you can make 2 attacks per turn, but missing whiffs and deals no damage, and you step down your damage die.
A natural 1 crits for your choice of double damage dice or inflicting the corresponding wound to the damage you dealt. A natural 20 is a critfail - automatically miss, and the GM picks another consquence.
You can parry a melee attack, which gives you +DEX to your AC against that attack, and disadvantage on your next attack. Must announce a parry before you know the outcome of the attack.
Weapons (credit to GLOG: Owlbear Stew Edition for list)
2. Bow: 1d6 ranged piercing damage, takes two hands to fire
3. Crossbow: 1d12 ranged piercing damage, takes two hands to fire, takes a STR check to load and fire in the same round (or takes full round to load)
4. Dagger: 1d6 slashing or piercing damage (your choice), can be thrown, 3 per inventory slot
5. Flail: 1d6+STR bludgeoning damage, ignores AC bonuses from shields.
6. Greataxe: 1d12+STR slashing damage, needs two hands to wield.
7. Greatsword: 1d10+STR slashing damage, needs two hands to wield, on 6+ damage target saves vs. disarming.
8. Halberd: 1d8+STR slashing damage, needs two hands to wield, enemies you hit are pushed 5ft in a direction of your choice.
9. Maul: 1d10+STR bludgeoning damage, needs two hands to wield, on 6+ damage target saves vs. knockdown.
10. Pike: 1d8+STR piercing damage, needs two hands to wield, double melee reach, can make an attack in response to a charging enemy that automatically crits if it hits.
11. Quarterstaff: 1d6+STR bludgeoning damage, when wielded in two hands, counts as dual-wielded.
12. Rapier: 1d6+DEX piercing damage, can riposte after successfully parrying and immediately attack at disadvantage.
13. Sabre: 1d6+STR slashing damage, on 6+ damage target saves vs. finger loss as Wound 6.
14. Scythe: 1d8+STR slashing damage, needs two hands to wield, double melee reach, can attack two adjacent enemies and deal half damage to each.
15. Spear: 1d6+STR piercing damage, can be thrown, on 6+ damage target saves vs. organ rupture as Wound 8
16. Stiletto: 1d4 piercing damage, can be thrown, 3 per inventory slot, can be well-hidden on person
17. Sword: 1d6+STR slashing damage, step up damage die when wielding with two hands.
18. Warhammer: 1d6+STR bludgeoning damage, on 6+ damage target saves vs. being stunned as Wound 1
19. War Pick: 1d6+STR piercing damage, on 6+ damage reduces target's armor by 1
20. Whip: 1d4 bludgeoning damage, double melee reach, can grab an object or limb on hit instead of dealing damage.
Armor and Shields
Leather armor: 2 AC, +1 initiative.
Chainmail: 4 AC.
Platemail: 8 AC, can't parry, -2 initiative.
Buckler: +1 AC and an additional +1 when parrying.
Light shield: +2 AC.
Heavy shield: +3 AC, but can't parry.
HP, Death, and Wounds
HP is ablative armor, representing your ability to shrug off and luckily avoid damage. Once you hit 0, you start taking hits to the meat that really hurt. You can keep fighting until your wounds become incapacitating. You might not really want to.
Damage that puts you at or below 0 HP also inflicts a Wound. Roll a d6 on the Wound Table and add the absolute value of your negative hit points (so rolling a 6 at -5 HP would give you an 11, massive internal hemorrhaging).
To get your HP at character creation, roll your Hit Dice with advantage, then add CON.
1. Stunned, save or you have disadvantage on all rolls next turn.
2. Light gash, save vs. bleeding for d3 damage (does not cause additional wound) each turn until you succeed.
3. Hand broken (d6, evens: left hand, odds: right hand), disarmed, disadvantage with that hand.
4. Deep gash, save vs. bleeding for d6 damage (does not cause additional wound) each turn until you succeed.
5. Ribs cracked. -1 Strength, -1 Constitution.
6. Lose d4 fingers (d6, evens: left hand, odds: right hand). Disarmed. -1 Dexterity, permanently.
7. Limb broken (d4, 1: left arm, 2: right arm, 3: left leg, 4: right leg). Arm: drop held item and arm useless. Leg: knockdown, can only crawl.
8. Organ ruptured. -2 to a random physical and random mental ability score.
9. Eye/ear lost. (d4, 1: left eye, 2: right eye, 3: left ear, 4: right ear). If second time receiving this wound to eyes or ears, blinded or deafened.
10. Concussion. Save vs. unconsciousness. -2 Intelligence, -2 Wisdom, -2 Charisma.
11. Massive internal hemorrhaging. Save vs. unconsciousness. -2 Strength, -2 Dexterity, -2 Constitution.
12. Gutted. Save vs. unconsciousness. Save vs. d6 bleed each turn until someone stitches you shut.
13. Lose a hand (d6, evens: left, odds: right). Save vs. unconsciousness every minute until you tie a tourniquet.
14. Lose an arm (d6, evens: left, odds: right). Save vs. unconsciousness every turn until you tie a tourniquet.
15. Lose a leg (d6, evens: left, odds: right). Unconscious. Save vs. death by blood loss every turn until you tie a tourniquet.
16. Skull split. Unconscious. Save vs. death. Lose 1 level and all abilities gained.
17. Spine severed. Unconscious. Save vs. death. Paralysis from waist down.
18. Disembowelment. Death.
19. Decapitation. Death.
20+. Chunkysalsafied. Death, everyone nearby saves vs. trauma.
A short rest takes 15 minutes of downtime and consumes 1 ration, you can't take more than HD short rests per day. Restore 1HD of HP and heal a wound 6 or less.
A daily rest takes 8 hours of combined sleep and downtime and consumes 1 ration. Reroll your HP, if it's higher than your current HP set your total to that, and heal a wound 12 or less.
A long rests takes 24 or more hours of sleep, downtime, and good meals. These conditions can only usually be found in town. Set your HP to the maximum and heal a wound 12 or less.