The Rune Magecraft that Touko had mastered certainly had offensive capabilities. Runes are a form
of Magecraft that makes the meaning of the engraved letters a reality by carving a powerful seal
into a target. If Touko were to directly inscribe the Rune of Sowilō, which represented fire, onto
Araya’s body, then his body would burst into flames.
... The weak point, however, was that the runes had to be inscribed directly, overlapping letters from
a distance wouldn’t work on Magi. Indirect magical energy would be repelled by a Magus who had
direct magical energy coursing through their body.

Kara no Kyoukai: The Garden of Sinners, Volume 5, Spiral Paradox 9 /12