Frustration inflicts damage and has no secondary effect. The base power of Frustration is dependent on the user's friendship. The lower the user's friendship is, the greater the base power of Frustration. The base power can be calculated using the following formula:
Power = (255 - Friendship) / 2.5
The power of Frustration varies between 1 (at the maximum friendship value of 255) and 102 (at the minimum friendship value of 0). The base power of Frustration is set to 1 if the formula outputs 0. If the user's friendship is 128 or more, Return is stronger than Frustration.
By leveling up