Combat
Combat is the ultimate challenge in most role-playing games. As such, the rules for it are more involved than the rules for other task resolution scenarios, which typically involve making a check of your stat modifier plus your skill bonus plus a d20 roll, which must meet or beat a target number (DC) to succeed. However, combat does follow a similar pattern. At its heart, a character makes a To Hit roll that is similar to a check, against a target number (AC) and if you meet or beat it, you have hit and may roll damage, which your target must then take. The To Hit roll is usually a STR modifier + character level + any class modifier + the result of a d20 roll. When using a light weapon you may use your DEX modifier instead of your STR modifier if you choose. When making an attack with a ranged weapon (instead of a close-combat, melee weapon) you must use your DEX modifier instead of your STR modifier.
Combatants take turns in initiative order. You determine initiative order by rolling a d20 and adding the DEX modifier to that roll for all combatants. The highest result goes first, and then the second highest, and then the third, etc. until all combatants have had a chance to take a turn. With any ties, the opponent with the highest DEX modifier should go first. For simplified opponents who do not have a listed DEX score, the PC will always go first in the case of a tie. This entire cycle of every opponent taking a turn is called a combat round. In theory, a round lasts a several seconds, and the actions you take during the round are somewhat abstracted (i.e., making an attack roll does not mean one swing of the sword. It includes abstracted back and forth of blows for a few seconds, feinting and trying to find a way past the opponent’s guard). On his turn, your opponent may also attempt to attack you. He will make a check with his To Hit score against your Armor Class (AC). Your AC is determined by adding 10 + your DEX modifier + your armor bonus + half of your level (rounded down). If, for example, you were playing a 3rd level Outdoorsman, who can use (and owns) medium armor, and had a DEX bonus of +2, your AC would be 10 + 2 (your DEX bonus) + 4 (the armor bonus for wearing medium armor) + 1 (your character level divided by two and rounded down) for a total of 17—a respectable AC that will protect you from the attacks of many opponents.
The To Hit and AC scores for your opponents are not necessarily calculated according to the same scheme as for player characters, as the game rule information for opponents is greatly simplified compared to characters.
If you successfully hit your opponent, you get to roll damage. Damage is determined by the weapon type; for example, a medium weapon does 1d8 damage. Add to this your STR modifier if it is a melee attack, or a ranged attack where your strength would have an impact (such as a thrown weapon attack) but not one in which you attack with a bow or firearm. This is how many hit points worth of damage you have done to your opponent. If your attack brings the current hit point total of your opponent to 0 or lower, then the combatant is in shock and falls unconscious and is at risk of death (see the Hit Points section for further details). Combatants are not in any way incapacitated after being hit unless their hit point total is 0 or lower. If your roll on a To Hit check is a natural 20, then a successful attack is a critical hit, and automatically does double damage. Do not simply multiply your damage, double your STR modifier, and roll the damage twice (so, for example, a critical hit with a medium weapon would do 2d8 damage rather than simply 1d8.)
While there is no technical limit to what you can do in a combat round, keep in mind that it’s only a few seconds long. Your GM may rule that certain combatants are far enough away that you can’t reach them in a single round, or that if you’re attempting too many things, that you won’t be able to do them all and you’ll have to cut some back. Rather than specify that you can have one or two (or whatever) actions per round and get into defining what kinds of actions you can do, we’ll leave this up to GM interpretation. In many combats, if the group are all standing relatively close, it is assumed that they can move around within the combat area and still attack the foe of their choice. If opponents are specifically trying to protect another combatant (like several fighters blocking access to a sorcerer, for example) then you may have to either sneak past, or fight past any such obstacles. Other obstacles, such as terrain, bushes, fruit carts, etc. that may infringe upon your freedom of movement are similarly up to the GM to adjudicate. He may require using the task resolution system by making checks to do certain things that you attempt.
Sorcerers may wish to cast spells in combat, since that is often their best weapon. Targeting an opponent with a spell works exactly like targeting one with any other kind of attack, although the stat used is not DEX nor STR but MND. However, many spells do not require a targeted attack to be cast—this only applies for spells in which a To Hit roll is required.
Combat continues until all of the combatants on a given “side” are defeated (0 hit points or less), or they have managed to flee the combat, or one side gives up and surrenders. Position in combat is also abstracted, and there is no combat grid, or tactical positioning supported by the rules. The GM should describe the scene, including answering any questions, such that questions of positioning or tactics are clear to all participants (i.e., if you can’t reach an opponent in melee because he’s behind a wall of protectors, that should be apparent from positioning, so you don’t attempt to attack that person with a melee weapon.) Players are also similarly encouraged to find solutions more interesting than “I attack it with my sword.” Because the solutions can be anything from, “I swing in to engage the baron on a hanging chandelier,” to “I splash a bucket of oil across the floor and set it alight with my torch,” it is impossible and in fact undesirable to give too much prescriptive guidance on how to handle these types of situations. GM’s are encouraged to use the task resolution system to determine the effects of such actions—pick the appropriate stat modifier, pick the appropriate skill bonus, and tell the player to make a check. Make a judgment call on the effects of a success or failure, either one.
If a character, NPC or monster attempts to flee a combat, their opponent may let them, or may choose to give chase. To break away from combat and initiate a chase, first the one running away must beat an opposed Athletics + DEX check. If the one running away does not beat the result of the check of the one who is trying to prevent him from running away, he is not able to break away from the combat cleanly and whomever he's directly engaged with automatically gets to make a critical hit against him. If he succeeds, then he runs away and the pursuer may choose to give chase. If he does, then both opponents make opposed Athletics + DEX checks. Terrain or other hazards may present a situational modifier to the check of one or more of the opponents. For example, if the character running away attempts to knock a pile of barrels into the path of his pursuer, that may create up to a -3 or -4 modifier to the opposed chase roll of his pursuer.
After five rounds of chasing, each combatant must make an Athletics + STR check (DC 15) or become fatigued from all that running. A fatigued character can still make opposed chase rolls, but will suffer a -5 penalty to the roll. If the character is successful on the check, he may continue the chase as normal, but will still have to roll to avoid becoming fatigued every round thereafter. Once a character is fatigued, he will remain fatigued for the remainder of the chase. If the chase ends in combat, a fatigued character will suffer a -2 to all To Hit and Damage rolls as well. The fatigued condition ends when the “action scene” is over and the character has a chance to catch his breath. Other modifiers can apply as well, determined by the GM. For example, if one character manages to mount a willing horse, he will gain a significant bonus (probably +10 or so) to his opposed check.
The chase is over when either the character fleeing manages to get away, or the character pursuing catches up to his opponent and the chase scene becomes, again, a combat scene between the two of them. Normally this will happen when one of the participants in a chase scene “wins” the opposed check by a difference of 10 or more. If the character fleeing beats the pursuer by more than 10, then he usually manages to break away and escape—unless this result make no sense, for example a chase on a wide open plain. If the pursuer, on the other hand, wins, then he has caught up to the one fleeing and the chase becomes a combat, following all of the rules of combat detailed above.
There are a few exceptions to this. If the environment allows, the one being chased might manage to duck into an alley, or into a barrel, or otherwise hide and lose his pursuer by making a Subterfuge + DEX check vs. the pursuer’s Subterfuge + MND check. Again; use the Skill + stat task resolution system, interpreting the stated actions by assigning which stat and skill best apply to resolve any other attempted actions. Apply and bonuses or penalties that the situation and environment may suggest. It is not meant that the rules be comprehensive in how to do this, as GM ruling and interpretation is the final arbiter in terms of how to resolve tasks.
Other Hazards
While entering into combat with deadly weapons is clearly a hazardous endeavor to those involved, adventurers may encounter a number of other situations on a semi-regular basis that may be perilous to their health. By design, this m20 system gives GMs tools with which to make rulings as he best sees fit, but here’s a few examples:
Level Advancement
Characters normally start at 1st level, but they may not at the GM’s discretion, and in any case, one hopes that characters who survive their adventures get better at having them after a time. One of the fun things about playing after a time is improving your character, which due to legacy and tradition issues is done through levels. Gaining a level, or leveling up happens at the GM's discretion, based on the pace that he wants the game to have. Personally, I prefer a pace that starts out relatively fast but slows down; i.e. moving from 1st to 2nd level takes 4-5 sessions, but advancing to the next level takes 6-7 sessions, and to third level may take 9-10 sessions, etc.
Each level adds the following to a character: 1) The maximum hit points of the character increases by 2. 2) +1 to all To Hit rolls. 3) +1 to all Skill modifiers. In addition, if the level divides by three (i.e. level 3, 6, 9) add 1 point to STR, DEX or MND. Don’t forget, if you play a Fighter, you gain +1 to their attack and damage rolls at levels 5 and 10. Experts gain new Affinities at 3rd, 6th and 9th level.
Although there’s no reason why you can’t go on from a mechanical perspective, this game is not meant to support levels above level 10. On average, at my pace, that would be at least a good 100 play sessions or more—about as long as I can stand to run a single campaign and deal with the same characters anyway.