From Crea Wiki
Every combat level you get in Crea will reward you with 2 Infusion Points to be spent on increasing your Stats. By finding Remna Cores in the game world and converting them into Infusion Points you can infuse one extra point per player level gained. This allows you to increase your skills by an extra 50 (at level 50) by converting Remna Cores. Each Stat also has a limit to how many points you can spend per character level. The Stats your character can grow and improve in Crea are Health, Stamina, Attack, Defence, Intelligence, Mind, Agility and Luck.
Each point in luck adds 0.25% critical hit chance.
Bows benefit from agility twice as much as attack. (2 parts agility, 1 part attack)
Swords and Lances benefit from attack. (3 parts attack)
Syle benefits from intelligence. (3 parts intelligence)
You can equip your character with many different items in Crea. There are different armor pieces that can be equipped such as helmets, chests, legs, shields, and accessories. There are different melee weapons such as swords, bows, wands, spears, and throwing equipment such as bombs.
There are also Talents.