Leon's knowledge of Karsus primarily comes from the game settings he encountered before the crossover, as well as word-of-mouth among players.
Karsus is undoubtedly the greatest arcanist of the Netheril Empire on the Ferren Continent, but his magical accomplishments and level of foolishness are equally astonishing.
His several follies caused different major consequences, the most famous being the invention of the only twelfth-level spell in history—Ascension Technique—which he used to steal the Magic Goddess Mishael's Divine Cloak.
This crazy spell needed divine approval to work and had a very short duration. Even with Karsus's unparalleled magical cultivation on the Ferren Continent, he couldn't bear the vast power of magic's essence.
