It was 03:10AM when Yuji got up from his slumber and decided to go for a morning jog around the academy premises, when he decided to take a rest and try his cultivation while trying to break the ceiling of the 4th magic circle which would be built around the heart and act as a protector for the heart in cases of stray magic out bursts which would cause the user to die of a magic strock strain.
With each breath he took felt heavier and heavier that he began to sweat because of his younger body with was not accustomed to the brutal training and ever increasing cultivation.
After five long hours of countless cultivation he finally broke through and attained 4th circle magic and only did it at a young age.