Stamina: Raise this to help your monster last longer in battle.
Strength: Purely for hitting the opponent harder.
Constitution: Aids defense and accounts for about 40% of HP.
Agility: Helps your monster's attacks hit, and helps them dodge better in battle. Also affects how fast your monster is.
Luck: An all-around stat that should be raised steadily with other stats. If you notice you're not gaining as much as you think you should from each stat, luck is probably why. Also governs the chance of getting and resisting a critical hit.
These are the actual stats you get from the primary stats, and directly impact battle.
HP: Keeps you alive! Representative of how many hits you can take after Defense filters out the damage.
Attack: Your raw attack power; how much you hit for in battle before Defense filters it out.
Accuracy: Your attacks won't land if your opponent's Dodge is too high.
Defense: In the event you do not dodge an attack, this helps soften the blow a little.
Speed: How fast your monster can hit your opponent; if they're a lot faster, they'll hit twice in the same round.
Dodge: Dodge your opponent's attacks. If it was a close dodge, they will hit you with a "glancing blow" for half damage.
= (stam * 2.7) + (con * 1.6)
= (str) * 1.05 + (luk * .5)
= (agi * .75) + (luk * .3)
= (con * .75) + (stam * .2)
= (agi * .8) + (stam * .2)
= (agi * .55) + (luk * .5)
Combat power is representative of how strong the monster is. In addition to splicing, it is also used to decide if you're too strong to be getting SRP from mob kills anymore.