Attack is a 武器 stat in 异度神剑 which determines the amount of Damage dealt by Auto-Attacks and Battle Arts, as well as the amount of HP restored by 治疗 arts. It is displayed as a minimum value and a maximum value separated by a hyphen, for example "180–310".
When a character auto-attacks or uses an attack or 治疗 art, the game chooses a random value between the minimum and maximum attack, and uses it to calculate the amount of damage or 治疗. However, due to a bug in the game's damage calculation, the random value is effectively limited to minimum+99, so a 武器 with an Attack of 180–310 will in practice be only 180–279. This bug is not present in 异度神剑 3D.
A weapon's maximum attack can be improved by Attack Plus gems which raise it by a percentage. The minimum attack can be improved by Attack Stability gems which raise it by a percentage, but cannot be higher than the maximum attack. When displaying the details for a 武器, the weapon's normal Attack stat are shown excluding any modifiers.
For example, if a 武器 has an Attack of 200–220, an Attack Stability 20% gem would add 40 (20% of 200), but since the weapon's maximum attack is 220, the minimum attack would be raised to 220. Adding an Attack Plus 10% gem would raise the maximum attack by 22 (10% of 220); combined with the Attack Stability 20% gem, the 武器 would then have an Attack of 240–242.