Book of Ki OGL Classes Explanation
From D&D Wiki
|This material is published under the OGL|
The following are the classes available using the Book of Ki, with their respective variants. Note that character classes not listed here are not recommended to be used in conjunction with this book.
 Ki User Classes
There are four character classes, which will be referred thereafter as ki user classes, these are: Monk, Book of Ki (DnD Class), Ninja, Book of Ki (DnD Class), Ranger, Book of Ki (DnD Class), and the Samurai, Book of Ki (DnD Class). Characters who take these classes are able to manipulate ki, and perform techniques.
 The Ki Pool
Ki users fuel their abilities through a reserve, or pool, of ki points. Your ki pool is equal to your base ki points gained from your class, bonus ki points from a high key ability score (see Abilities and Performers, below), and any additional bonus ki points from sources such as your character race and feat selections.
 Multiclass Ki User Characters
If you have levels in more than one ki user class, you combine your ki points from each class to make up your reserve. You can use these ki points to perform techniques from any ki user class you have.
While you maintain a single pool of ki points from your class, race, and feat selections, you are still limited by the performer level you have achieved with each technique you know.
 Abilites and Performers
The ability that your techniques depend on—your key ability score as a performer—is related to what ki user class (or classes) you have levels in: Intelligence (ninja), Wisdom (monk, ranger, samurai), and Charisma (samurai). The modifier for this ability is referred to as your key ability modifier. If your character’s key ability score is 9 or lower, you can’t perform techniques from that ki user class.
Just as a high Intelligence score grants bonus spells to a wizard and a high Wisdom score grants bonus spells to a cleric, a character who performs techniques gains bonus ki points according to her key ability score.
How To Determine Bonus Ki Points: Your key ability score grants you additional ki points equal to your key ability modifier x your performer level x1/2.
 Combat Modes
Every being that possesses ki points manages them in combat through combat modes. All such characters have the standard combat mode plus an additional combat mode of the character’s choice. Combat modes are obtained together with the ability to possess and use ki points, and the additional combat mode chosen will be the combat mode that subject will have for the rest of her life.
Combat modes allow you to draw ki points from your ki pool, that is, you gain a certain amount of ki points, which are taken out from your daily ki point allotment (you can never draw an amount of ki points greater than the remaining points in your ki pool). Regardless of the combat mode you use to draw ki points, unspent ki points return to your ki pool after every encounter.
Standard Combat Mode: All characters with ki points can use this combat mode to draw ki. You can draw 1 ki point per level you have attained by meditating for 1 full round; alternatively, you can draw 1 ki point for every 2 levels you have attained by meditating for a standard action, or 1 ki point meditating for a move action. You can’t draw ki points more than once per round using this combat mode.
Meditating any amount of time provokes an attack of opportunity, and while meditating you lose your class bonus as well as any Dexterity bonus to Armor Class. If you are struck while drawing ki points, you must make a Concentration check (DC 10 + damage dealt) or gain no ki points instead. You must also make a Concentration check when attempting to draw ki points while grappling or pinned (see the Concentration skill in Chapter Four for more information). The flow of ki is visible as a flow of energy around you and is also audible as a current of air.
Additional Combat Modes: Besides the standard combat mode, a character must choose an additional combat mode from the following list.
Defense Combat Mode: You draw 2 ki points every time you successfully block or dodge an attack made by an opponent (every time an opponent fails to hit your AC). In addition, every time you successfully block or dodge all attacks made by an opponent in a given round, you draw 2 more ki points. Only normal attacks allow you to gain ki points this way, blocked or dodged extra attacks from techniques or other sources do not let you draw ki points.
Hit Combat Mode: Every time you make an attack against an opponent you draw 2 ki points. An attack has not to be successful to draw ki points. Only normal attacks allow you to gain ki points this way, techniques or other means of attacks do not let you draw ki points.
Rage Combat Mode: You gain 1 ki point per every 2 points of damage dealt to you, if you heal this damage, naturally or supernaturally, you lose ki points accordingly.
 AC Bonus
Some classes presented here have an AC Bonus (similar to the Defense Bonus described in Unearthed Arcana). This bonus to Armor Class is gained by deflecting hits using a melee weapon or unarmed strike (you must be armed to get the bonus), and it is considered a shield bonus. Although, unlike normal shield bonuses, this bonus is lost when flat-footed, jumping, landing or falling; it is also lost against an attacker on a lower or higher ground. You also lose your AC bonus whenever you’re denied your Dexterity bonus to AC and against attacks of opportunity.
 Vitality and Wound Points
This system uses the Vitality and Wound Points variant described in Unearthed Arcana. If you don’t want to use this variant, replace vitality with hit points. Use the given vitality die of the new classes as their respective hit die.
It is recommended to use the “Armor as Damage Reduction” variant described in Unearthed Arcana. The Armor Bonus provided by armors should stack with the class bonus to AC, but should not stack with shield bonuses.