What Am I Lacking?

( Leo's POV, after completing intermediate mastery)

[System Notification: Congratulations to player 'TheBoss' for improving your skill [Mirror World] to (Intermediate) mastery.]

*Exhale*

Leo exhaled in relief as the notification appeared before him.

This had undoubtedly been the most difficult challenge he had faced in his quest to raise the mastery of any skill.

The journey to (Intermediate) mastery had pushed him to his limits, and had left him utterly drained, however, to his surprise, although he reached the (Intermediate) mastery of [Mirror World], the much awaited system notification that he had become a 'Master' warrior, never came.

To reach the (Intermediate) grade of mastery, he had not only been forced to refine his control over mana, but also forced to push his mental capacity to the brink, using every ounce of concentration that he could muster.