When fighting, in any battle, characters will have HP, MP, and AP.
Statistics in Kingdom Hearts refer to the player characters', and his party members', personal attributes such as level, Hit Points (HP), Magic Points (MP), Ability Points (AP, used to equip abilities), Strength, and Defense.
Leveling up is done through collecting Experience, which can only be gained through defeating Heartless and other enemies. The amount of Experience depends on the enemies' level and overall strength. Experience is also shared across all characters, whether they are in the party or not. Each time anyone levels they gain an increase to a specific stat, such as HP (+3), MP (+1), and Str, Def, and AP (all +2). The actual total end result for everyone varies, but Sora specifically gains the most balanced amount. Other stats that can increase upon leveling are the maximum number of item and accessory slots. By Sora, I’m referring to the main player in each different world and storyline that we’ll progress through.
As your MP increases, you’ll get a much broader variety of Magic. These are all the spells you can use (with the MP cost):
Fire: 3 MP, 5 damage.
Fira: 10 MP, 15 damage.
Firaga: 50 MP, 70 damage.
Firaza: 150 MP, 225 damage.
Water: 5 MP, 8 damage.
Watera: 15 MP, 23 damage.
Waterga: 60 MP, 80 damage.
Waterza: 175 MP, 250 damage.
Thunder: 8 MP, 10 damage.
Thundera: 18 MP, 28 damage.
Thungaga: 70 MP, 90 damage.
Thundaza: 200MP, 275 damage.
Blizzard: 10 MP, 13 damage.
Blizzara: 20 MP, 30 damage.
Blizzaga: 75 MP, 95 damage.
Blizzaza: 225MP 300 damage.
Aero: 12 MP, defense for 1 turn.
Aerora: 22 MP, defense for 3 turns.
Aeroga: 75 MP, defense for 7 turns.
Aeroza: 220 MP, defense for 15 turns.
Stop: 15 MP, skips enemy turn once.
Stopra: 25 MP, skips enemy turn 2 times.
Stopga: 80 MP, skips enemy turn 3 times.
Stopza: 250 MP, skips enemy turn 5 times.
Gravity: 20 MP, 30 damage.
Gravira: 35 MP, 50 damage.
Graviga: 80 MP, 100 damage.
Graviza: 275 MP, 325 damage.
The list will increase through time.
Now, for AP.
Ever since the first installment in the series, there have been a lot of abilities that let Kingdom Hearts players grow stronger, and make the game either easier or harder. Newcomers may not know which ones to use once they have too many abilities and not enough AP (Ability Points).