The stats are used in the Battle Arena
forum. You invent a character and can fight them against other members' characters, either as just a spar or a modded battle. This is where the stats come in. A moderator will adjust stats with each attack (or series of attacks) until a victor is found.
HP represents your Health Power. This reduces as you get injured.
MP represents Magic Power. This gets used as you use spells.
PP represents Physical Power. This is used for Physical Attacks.
Exp shows how close you are to the next level and Commitment can be used by other posters to reward you for good roleplaying, or punish you for poor roleplaying or abandoning quests and duels before their completion.