There were about three hundred men in the cavalry troop. They were all clad in sturdy metal armors and displayed great discipline in their actions—unlike the knight-wannabes that Grimm saw amongst the nobles or the lowly uncivilized "knights" who visit the pubs.
These knights were… basically an army of their own.
According to what Grimm knew, most areas of the Seven-Ring Holy Tower Academies, not just the Eastern Coral Island, were split into various sections according to their sorcerers' castles and nobles.
It was unthinkable for the nobles, who usually were only interested in indulging in luxury and pleasures, to want to organize a fully trained army.
After all, no matter how strong the knights they acquired, these warriors were nothing but papers in the eyes of the sorcerers. In the eyes of the sorcerers, these knight-cavalry recruiting was entirely pointless.