After the dust from the explosion settled down, all the students sighed in relief. That was because Rein was covered in a hexagonal barrier and was holding a ball-like device in his hand. Some of the students who were familiar with the latest technology immediately recognised the item to be recently invented Impregnable Protector mark 2, that the Dark Aqua Conglomerate had developed recently.
This was a high tech shield device that was able to stop even very strong attacks. But the fuel that it used was very precious so very few people had the ability to use this item.
Obviously Rein was able to stop the previous explosion with his own powers but that would expose his true powers to the other students. Rein was perfectly fine with showing it to the people who had attacked him as they would not stay alive for long. But obviously he could not do the same with the students.