Sienna wanted to tell Charles just that. Be it the Humerus Wyrm or the Legendary-realm Lich, all of them were defeated by Mage Felic, who was heaven-defyingly powerful. However, he glanced at Ujfalusi before he said so, and immediately decided to shut up.
Nobody liked other people talking about their failures and defeats, even if the one who defeated him had become his master. Sienna didn't know if this was a taboo topic for Ujfalusi, but putting himself in Ujfalusi's shoes, he wouldn't want others to talk about it. Although Ujfalusi was already an attendant of Mage Felic, he could still kill Sienna easily at the snap of his fingers as a powerful Lich.