Combat

Combat is where the rules tighten into clockwork. The loose exchange of the conversation becomes a measured sequence — initiative, surprise, attack rolls, damage, saving throws, and the quiet arithmetic of hit points. Learn the engine and it runs itself; the drama comes from what you decide to do with it.

The time it runs on

A battle is measured in rounds of about a minute, each split into ten segments of a few seconds. Most combat actions fit inside a round; the slow and mighty — casting a big spell, swinging a polearm — reach into later segments or further rounds. Ten minutes of exploration is a turn; ten rounds is a turn. When blades come out, time slows to the blade's own clock.

Initiative

At the start of a round, each side rolls 1d10 (or each combatant for individual initiative). Low rolls act first. Add your weapon's speed factor, or your spell's casting time, to your roll — a dagger moves before a two-handed sword, and a spell you are shaping goes off only after the thrum of its casting. The alert, the quick, and the well-positioned act sooner; the surprised act not at all.

Surprise

When two sides meet unexpectedly, each rolls 1d6. A result of 1–2 (or 1–4 for those who move like shadows — elves, halflings, thieves) means that side is surprised and loses one or more segments of action while the other side moves freely. A surprised foe cannot act, cast, or flee — which is why scouting, silence, and a thief in the shadows win fights before they begin.

The attack roll

To hit, roll 1d20 and add your modifiers. You succeed if the result equals or exceeds the number you need — your THAC0 (your class's base chance, which falls as you rise) minus the target's Armour Class.

Example: A veteran with THAC0 16 swings at a foe in chain (AC 5). The number to hit is 16 − 5 = 11. After a strength or magic bonus is added, a roll of 11 or better strikes home. The same hero against a foe at AC −2 needs 16 + 2 = 18.

The d20 is the one die where higher is better for hitting. A natural 20 strikes true no matter what; a natural 1 misses regardless.

Modifiers

Many things tilt the roll. A strength bonus aids melee, a dexterity bonus aids missiles, and magic adds its own edge. Circumstance matters just as much: attacking from behind (+2), charging (+2), holding higher ground (+1). And the enemy fights back with cover and concealment — light cover −2, heavy cover −8 — and with movement that makes you miss. Called shots and off-hand weapons cost you accuracy for effect. Read the situation, not just your sheet.

Armour Class, the other side of the coin

Your Armour Class is how hard you are to hit, and lower is better. It is the target number the enemy beats. Cover, being prone against missiles, and shields all shove it down; being blinded or held shoves it up — and a held or paralysed foe is hit automatically. A character who cannot move is a standing target.

Damage

When an attack hits, roll the weapon's damage die and add your modifiers — Strength for melee, specialisation for warriors, magic wherever it applies. Subtract the total from the target's hit points. Hit points are not just flesh; they are luck, will, and the will to keep standing, and they are the one resource nobody can spare. When they reach zero or below, you are down — dying, dead, or at the referee's mercy, depending on the wound.

Saving throws

Some dangers are opposed not by armour but by the raw power of your own body and soul: poison, petrification, breath weapons, and hostile spells. When such a thing strikes, you roll 1d20 against one of your class's saving throws — the Paralysis/Poison/Death, Rod/Staff/Wand, Petrification/Polymorph, Breath Weapon, and Spell categories, each with its own number by class and level. Roll equal to or over to succeed. A natural 20 always saves; a natural 1 never does.

Success softens the blow: half a fireball's damage, a charm shrugged off, a petrification resisted. Saving throws are the difference between a horror story and a narrow escape — and the difference is often one point.

Death, healing, and recovery

When your hit points hit zero, matters turn grave. The referee decides the specifics of your table — a hero may be dying and revivable with quick healing, or dead outright and in need of a priest's prayer. Healing comes from priests' spells, potions, and rest; a day of rest mends a little, and magical mercy mends a lot. The resurrection that brings you fully back is the province of high priests and great cost, and it taxes body and soul — your system shock survival after that long dark.

The craft of a fight

Know before you swing: a warrior is a wall and a hammer, a thief is a knife in the dark and a scout, a wizard is a prepared storm and a priest is mercy and a shield. Fight as a party, not as six solo heroes; hold the torch, guard the caster, count the exits, and remember that the retreat that saves the party is a victory. The monsters you face in the Monsters compendium are built on the same physics you are — hit dice, Armour Class, THAC0, and hit points — so the numbers you have learned to read on your own sheet are the same ones that tell you how a dragon is afraid. Fight well, and win the fights you choose.