Infiltrating the Principal Tower

In the middle of a moonless night, Ace's invisible figure crossed miles and carefully made his way towards the principal tower, which was the largest and most magnificent building of the imperial school; it could see from all the way to the entrance. 

But others can see it; this didn't mean anyone could approach it because there were layers of restrictions in the way, and at a certain point, there was a forbidden zone, and anyone who dared to enter this area without permission would suffer. 

The principal tower was the symbol of the Sky Heart Imperial School, and all the imperial teachers, vice principal, and principal lived there, so everyone was careful not to cross the line. 

However, in recent years, other than the school's top powerhouse, the imperial clan's direct descendants were allowed entry into the Principal Tower so they could privately learn from the imperial teachers and not come in contact with just any random nobles.