It was quite ironic that Arthur, an uneducated person who had to drop out of school, would receive an ability containing the word 'wordsmith.' After his dinner with Emma, Arthur came back home and looked the word up.
Wordsmith, someone who skillfully uses words. If he combined that meaning with runes, that his ability would mean someone who skillfully uses runes. Another word that popped out was a 'writer.'
Arthur has always used his runes like skills, but past incidents proved otherwise. When he was in the trial, he was able to set conditions for the ring to alert him of incoming monsters. When he saved Hazel, he altered his detection rune's range of work by expending mana. With Dimon, he targeted a specific poison using his heal rune.
