Mikel had slowly been gaining the knowledge that shamans were not all the same. There were different types of them, just like Ran and Tahu. But most importantly, it all boiled down to one's spiritual energy—and its limitations.
According to them, everyone was born with spiritual energy. It was just that the majority of people were born with weaker spiritual energy, limiting their ability to see beyond the world of the living. Some only manifested theirs later in life.
It could also be unlocked through accidents or traumatic incidents.
But even then, there was a limit to one's spiritual energy. They could increase their capacity with patience, understanding, and training—something the academy offered. However, even that had boundaries.
A shaman could only wield as much spiritual energy as they were capable of handling and had trained for. Otherwise, using power beyond their limit had consequences. Just like Eron. Just like Mikel during the fight with the Type X.