Master of Lightning

This is the story of an orphan of the 1349 plague, who became a monk, and eventually became a hero and legend.
His special knowledge and skills developed in the monastery made him dangerous to his enemies, but put in danger those who would help him and those who were very close to him.

Included as part of the story is a sample of his writing, which has confounded many over the ages. Could it hold clues to the source of his powers?