Spellcasters in Numira are called "Markbearers" or the "Marked". To begin channeling magic, one must inscribe a Spellmark into their flesh. It is a bloody ritual, but it's a sacrifice that many choose to make.

World Codex

Magic has shaped every part of Numira. Even the mightiest army can easily be defeated by a few powerful Markbearers. Arcana, however, requires the souls of the dead as fuel.