The battles in the Kingdom Hearts series are based upon a system of Hit Points (HP) or also known as Health Points.
Each character and enemy has a number of Hit Points that must be depleted before he/she/it is defeated. To deplete Hit Points, that character or enemy must be hit by an attack or spell that causes damage. The amount of Hit Points taken away with each hit depends on the attacker's strength and the target's defense. A higher defense means that fewer points are taken away with each hit, and higher strength means that more points are depleted.
Allied characters' HP can be seen next to their picture on the Heads Up Display, and, if the player has the Scan ability equipped, the enemy's HP can be seen on the top of the screen when targeted.
Allied characters' HP can be restored via HP orbs, Potions, Hi-Potions, Mega-Potions, Elixirs, Megalixirs, and Cure Magic. Some enemies have the ability to regenerate their own HP, but this is not common.
If HP of the player's character (the main character, normally Sora) is fully depleted, the player will then receive a Game Over.
Hit Points are displayed in a bar form. When a character's HP is at 100%, the bar is completely green. When damage is taken, the picture of the character on the meter, such as Sora, flinches momentarily and part of the green becomes dark gray, signifying that Sora is not at full health. In most games, the HP bar extends in length as Sora's maximum HP increases.
When HP reaches a very low point, Sora goes into critical mode. The HP meter will then flash red and a siren will go off. This is to warn the player that Sora is low on health. This carries on into Kingdom Hearts: Chain of Memories and Kingdom Hearts II and also applies to Roxas, Riku, and Mickey Mouse when they are playable. In Kingdom Hearts 358/2 Days and Kingdom Hearts Birth by Sleep, the character portraits do not flinch, but merely flash red when taking damage. The HP bar also flashes yellow when picking up Mission Point prizes in Kingdom Hearts 358/2 Days. As in past games, an alarm still sounds when low on health.
The HP bar of the player character is often located to the bottom-right or top-left corner of the screen, grouped with all other gauges displayed during gameplay. In Kingdom Hearts II, the HP bar appears next to the MP and Drive Gauges. It only appears next to the MP Gauge in Kingdom Hearts, and the HP and MP gauges shift position depending on how much HP and MP Sora has. In Kingdom Hearts: Chain of Memories, it appears next to Riku's DP Gauge in Reverse/Rebirth. In Kingdom Hearts Birth by Sleep, it appears next to the Focus and D-Link Gauges. In Kingdom Hearts 358/2 Days, no other gauges appear, but the Limit Gauge serves as, at most, half of the player's HP bar.
The exact appearance of the gauge varies depending on the game. In most games it appears as an up to 270 degree green arc which extends in a straight line horizontally after 270 degrees. In Kingdom Hearts: Chain of Memories, Kingdom Hearts: 358/2 Days, and Kingdom Hearts: Re:coded, the gauge is instead a horizontal bar with no arcs.
In Kingdom Hearts: Chain of Memories, there is a second blue HP gauge that appears below the green HP bar if the maximum HP is greater than 280. The blue HP gauge must be depleted before the green gauge begins to run out. This second gauge is based off that of bosses in that game, in which the second HP gauge was blue.
Enemy HP bars have several appearances as well which vary depending on the game. In Kingdom Hearts, the standard meter is green and the length of the gauge is determined by the enemy's maximum HP. Additional gauges which appear if the enemy's current HP is above a certain amount will appear as yellow, then orange, then red, then purple on top of the green gauge. If an enemy had more health than could be displayed in 5 meters, then it would appear as if no damage was occurring, until the amount of health could be displayed in the 5th bar. In Kingdom Hearts: Chain of Memories, the HP of enemies are displayed in a similar way, with the first gauge being green. Blue, yellow, and red gauges will appear if the enemy has enough HP.
In Kingdom Hearts II, Kingdom Hearts Re:Chain of Memories, Kingdom Hearts coded, and Kingdom Hearts Birth by Sleep, instead of representing large amounts of HP with different colors, the amount of HP is instead represented by green squares underneath the HP bar representing extra gauges. The same thing was done in Kingdom Hearts 358/2 Days, except little ovals are used instead of squares to represent multiple HP bars.
The party characters also have HP gauges shown on screen, and the appearances of these also vary across games. In Kingdom Hearts, the HP and MP gauges of party characters are shown at the top right of the screen and are virtually identical in appearance to Sora's HP and MP gauges, but are smaller and the MP charge is not shown.
In Kingdom Hearts II, the HP and MP gauges appear as two half arcs arround a circle, and are located just above the player character's HP gauge.
Increasing maximum Hit Points
In each game, the way in which one can increase Sora's max HP differs. In Kingdom Hearts, additional HP was automatically increased across several level ups. In Kingdom Hearts: Chain of Memories, increasing max HP was an option upon level up, along with increasing the deck size and learning a new Sleight when playing as Sora, and increase Attack Points and Dark Points when playing as Riku. In Kingdom Hearts II and Kingdom Hearts Birth By Sleep, max HP is increased as a reward for completing certain tasks, usually defeating a Boss, or by equipping HP Boost. The maximum Hit Point total in Kingdom Hearts Re:Chain of Memories is 560.
In Kingdom Hearts, the overall number of Hit Points obtained throughout the game depends on what weapon the players chooses at the start. The most Hit Points can be obtained if the player chooses the Dream Shield, this enables Sora to reach a maximum number of 111 HP by the end of the game. Likewise, each of the three Dream Weapons correspond with either Strength, Magic, Defense, or HP.
In Kingdom Hearts II, the maximum number of Hit Points for Sora is 120 regardless of what weapon the player chooses at the start of the game.
Accessories that boost max HP when equipped are another method, and are recommended when starting HP totals for characters are lower early on. Donald suffers from the lowest HP in both Kingdom Hearts and Kingdom Hearts II and it is recommended to outfit him with several to compensate for this deficiency.
In Kingdom Hearts 358/2 Days Story Mode, Roxas begins with 62 max HP and his level increases the max HP by 3. In Mission Mode, the max HP differs around characters. Lexaeus has the highest max HP status and Zexion and Donald both have the lowest. Max HP can only be increased by leveling up or installing a ring panel that increases max HP.
Reducing loss of Hit Points
An ability called Second Chance changes critical hits (those which would decrease HP to 0 or less) to hits that merely reduce HP to 1, except when HP is already 1.
- The maximum number of Hit Points for a particular character varies from game to game. For instance in Kingdom Hearts Final Mix, the final HP values for all the characters has been increased due to the new accessories that have been introduced and the level bonuses that have been tweaked. The overall number of Magic Points have also been changed in each game's respective remakes, again because of newly-introduced weapons and accessories.
- In Kingdom Hearts Final Mix, the Magic and Hit Points would reach the same point together, indicating that they have reached their maximum level. However, in Kingdom Hearts, it can be noticed that the HP and MP meters will not always reach their maximum at the same length.
- In each game, the numbering system for HP differs: the actual numerical values relate to the HP bar in the HUD on-screen. Kingdom Hearts Final Mix, Kingdom Hearts II, and Kingdom Hearts II Final Mix versions are the only exceptions because they all share the same numbering system.
- In some games higher difficulties affect the maximum HP a character can obtain. For example, in Kingdom Hearts II Final Mix's Critical mode the maximum HP is 60, while it is increased to 120 in easier modes. This is due to the HP bonuses in Critical mode being halved.