One moment Nero was all alone, and the next he was just there. The only explanation he could think of was some kind of teleportation card or ability, but that was highly unlikely. The alternative was that the man in front of him was so fast, that Nero hadn't seen him move at all!
But how could there be no afterimage or trace at all? No matter how fast one moved, it couldn't seem instantaneous, right? Then again, he was just musing on how versatile cards actually were.
Nero had his spear raised already by the time he finally got a good look at the man, and realised he knew who it was. It was the major incharge of their training. Why would the major himself come here?
Even if the incident here was detected, and the army responded, the major did not need to come personally. Even a sergeant was more than enough, to be honest.