Statistics, or just Stats, are a numerical value placed upon characters to measure their capability in certain areas. There are 7 stats with a numerical representation; these stats may be changed as the character levels up and earns stat points to distribute, or by training in certain areas. There are 3 stats whose numerical representation cannot be seen, and is instead displayed by a letter grade; they're known as Hidden Stats, one of which cannot be altered by leveling up since it's a fixed amount.
When a Character levels up, they may gain an additional number of stat points for their effort and experience during the process of growth; the least amount of points that can be earned is 15 and the most is 40, distributed according to the Character's playing style. The amount of points gained is determined by how much they have actually experienced doing rather than how much fighting they've done. As such, it's possible to level entirely on simply traveling and interacting with people and still gain significant amounts of points, the same or more than people who purely rely on killing monsters.
Affects physical damage, stamina, and max weight a Character can carry.
Affects physical defenses without armor and health amount. Those with high Vitality will also be able to resist most ailments.
Affects weapon attack speed, as well as physical attack accuracy and reflexes.
Affects speed in and out of battle, acrobatic ability, and dodge rate.
Affects magic power and magic defense. Also affects magical accuracy.
Affects magic power and mana, as well as spell/ability/skill development. It doesn't affect magic power as much as Intelligence does; people with high Wisdom but low Intelligence won't have very impressive destructive magical capabilities, but they will have a wider range of spells in their arsenal.
Affects how other people react to the character. A high Charisma means a character may get free things from shops, secret quests from NPCs, or they'd successfully be able to talk their way out of a tough situation. Low charisma means the character is more likely to be swayed by others with a higher score.
A hidden stat, Luck has a set value from character creation; it will be a number from 1 - 70, with the letter changing every 10 points(F being the lowest grade, C being Average, and S being the highest possible). It can be increased or decreased with bonuses or effects from items, potions, or spells, but all those will wear off. There's no such thing a permanent Luck boost. Luck affects everything in a minor way, and is responsible for things such as item drops or rare events.
Health Points, or HP, are a Hidden Stat and as such is represented by percentages instead of actual numerical values; even someone with a skill that allows them to see Health and Mana bars will only see percentages. It is displayed as % / %, because things like injuries, spells, or enchanted armor could rise or lower the total percentage you have available and the second number reflects that. The first number reflects how much of the second number is available. Someone with a lot of armor increasing their health could have an HP bar of 100% / 500%, 500% meaning they have 400% more health than their base amount, and the 100% meaning they are completely uninjured.
Mana Points, or MP, are a Hidden Stat and as such is represented by percentages instead of actual numerical values; even someone with a skill that allows them to see Health and Mana bars will only see percentages. It is displayed as % / %, exactly like the Health bar, using the same system. Spells, buffs, enchantments or even illness can affect how much total MP the person has, shown as the second % on the bar, while the first % shows how much of that amount is available is available for use.