There are several stats in Arcane Online, like your HP/MP, the 4 base stats (STR, INT, AGI, STA) and other attack and defense stats.
Generally speaking, the 4 base stats influence nearly all the other stats and should be the one to focus on when possible.
Besides those stats, the Warrior’s shield can hold a special enchantment called Shield DEF which increases the Warrior’s Physical and Magical Defense by 25% when it procs (the Shield DEF increases with STR and the Enchant on Shield, at level 60+ it can be around 35% by stats and an additional 7~20+% by Enchant)
Note that Elementswork differently. They will just add extra damage on every attack using the formula:
Your Element X Attack – Target’s Element X Resist (or vice versa)
So if you have 100 Fire Damage and the opponent has 40 Fire Resist, each of your attacks will add 60 Extra Fire Damage (and so on for the 5 elements)