Weapons Weapon Lv. 1 - Every +1 upgrade gives 2 ATK, 0~3 ATK for every Over Upgrade pass the +7 safety limit, and ? ATK for every High Upgrade pass +15.
Weapon Lv. 2 - Every +1 upgrade gives 3 ATK, 0~5 ATK for every Over Upgrade pass the +6 safety limit, and ? ATK for every High Upgrade pass +15.
Weapon Lv. 3 - Every +1 upgrade gives 5 ATK, 0~8 ATK for every Over Upgrade pass the +5 safety limit, and ? ATK for every High Upgrade pass +15.
Weapon Lv. 4 - Every +1 upgrade gives 7 ATK, 0~14 ATK for every Over Upgrade pass the +4 safety limit, and 12 ATK for every High Upgrade pass +15.
A +20 level 4 weapon gives 201~424 extra ATK and MATK.