Player characters are described, in game terms, by a set of statistics that define their abilities, strengths, and weaknesses in the game world.
The basic physical and mental strengths and weaknesses of the character. There are 6 ability scores: Strength (abbreviated STR), Intelligence (INT), Wisdom (WIS), Dexterity (DEX), Constitution (CON), and Charisma (CHA). A character is ranked in each ability score by a number between 3–18. (3 being the worst score possible and 18 the best.)
An adventuring profession to which the character belongs. A character’s class defines their main abilities. (Classes are detailed in the genre rules books in the Old-School Essentials line.)
Unless a demihuman class is selected, the character is assumed to be human.
The character’s experience as an adventurer is denoted by their experience level. Characters typically start play at 1st level (the lowest level of adventurer) and can increase in level through successful adventuring. As a character goes up in level, they gain more powerful abilities, as defined by their class.
Experience Points (XP)
The character’s advancement in the game is tracked by the accumulation of experience points. Experience points are awarded by the referee after a successful adventure. When the character has accumulated a certain number of experience points, the character’s level increases. Each class specifies the number of experience points required to achieve each experience level.
The ability score (or scores) that are the most important to the character’s class. The character’s score in these abilities can affect the rate at which the character accumulates experience points.
The character (and every other creature in the game world) is aligned with one of three cosmic principles: Law, Neutrality, or Chaos (see Alignment). This alignment determines how certain magic influences the character and should be used by the player as a guideline for role-playing the character.
Hit Points (hp)
The character’s ability to avoid dying. The character has a maximum hit point total and a current hit point total, which are tracked separately. When a character is harmed, their current hit point total is reduced. If this number reaches 0, the character is dead! Rest or healing can restore lost hit points (see Damage and Healing), but never above the character’s maximum hit point total (this is only increased when the character increases in level).
Hit Dice (HD)
The number of dice used to determine the character’s maximum hit point total. The character’s class determines the type of dice rolled (i.e. d4, d6, d8) and the character’s level determines the number of dice rolled. (Some classes also grant a flat bonus to hit points at certain levels, instead of or in addition to an extra HD.)
Armour Class (AC)
The character’s ability to avoid damage in combat. Armour Class is determined by the character’s Dexterity score and by the armour they wear. Lower AC scores are better, so a bonus to AC decreases the character’s AC score and a penalty increases the AC score.
Attack Roll “to Hit AC 0” (THAC0)
The character’s ability to hit foes in combat, determined by their class and level. Lower THAC0 scores are better. See Combat for full details on attacking.
Saving Throw Values
The character’s ability to avoid being affected by certain types of dangerous or detrimental effects. There are five saving throw categories: death (or poison), wands, paralysis (or petrification), breath attacks, spells (or magic rods or staves). The character’s saving throw values are determined by class and level. See Saving Throws for full details.
The speed at which the character can move when exploring, travelling, or during combat. Every character has a base movement rate and an encounter movement rate (noted in parentheses). The encounter movement rate is one third of the base movement rate. The default movement rate for characters is 120’ (40’)—a base movement rate of 120’ and an encounter movement rate of 40’.
Finally, the character’s class denotes a set of special abilities that the character may use. These include the ability to use certain types of armour and weapons and the ability to speak one or more languages.
Ascending AC (Optional Rule)
Some groups are more familiar with an Armour Class system where higher scores are better. This system is known as Ascending Armour Class (abbreviated AAC) and works as follows:
- Armour Class: When using AAC, higher scores are better. Bonuses to Armour Class increase the AAC score and penalties decrease it.
- Attack rolls: Instead of referring to an attack matrix (see Attack Matrix by THAC0), attack rolls involve the use of an attack bonus which is added to the d20 attack roll (see Combat).
- AAC scores: AC scores for monsters and equipment are followed by the equivalent AAC in square brackets.
- Attack bonuses: THAC0 scores for monsters and classes are followed by the equivalent attack bonus in square brackets.
Note: Using Ascending Armour Class results in very slightly different attack probabilities than when using the traditional approach of descending AC with an attack matrix.