The Reverse Family might not hold a lot of strength, but no one dared to offend them. Otherwise, the runes they uncover and the instructions to create them will never reach the offender. However, Julia took a strong stance against Casca even before he managed to hurt Arthur.
The earlier help was nothing compared to this, and Arthur knew that. Julia was risking her future as a runemaster for his sake, and it might be the first time someone he barely knows does that.
"Julia Vinera," muttered Casca as his focus shifted to her. "Are you willing to risk our relationship for this man? If he turns out to be lying, then he will be banished as a runemaster. As for you, the Reverse Family will forbid your usage of any runes we uncovered."
"You did not do this for the other students," Julia held her hands behind her back as she puffed her chest. "The fair thing to do is to summon every applicant and ask them to prove their ownership of the runes."