He then searched the bag a bit more only to find the mana device that all the students on the campus were wearing. Even without touching it, Rex could tell that the device was imbued with tracking magic, safeguard magic, basic defense magic, and basic healing magic that would activate when the host's life is in danger.
Although they weren't the strongest spells, they were still something that could come in handy, at least for those whose mana would be depleted. In a tough situation, even a little of those spells could make a difference. Of course, the host can activate those spells even when he wasn't in danger.
The problem is, that he or she could use it only once and hence have to send the device to the teachers or experts to add the magic again. Students were strictly prohibited to tamper with spells or add anything to the device without the faculty's permission.