Yeyin had just seen Isabella escaping from those two Candidates and hurriedly blipped out a wisp of her aura. Due to the range and limited soul sense, only Isabella was able to pick it up, while Girias and Harmon failed to sense it.
She used that to her advantage, using a concealment technique she learned from the Noble Phoenix Moon Shade Art, the Body Tempering Cultivation Manual of the Ice Phoenix Clan used by humans and feys alike.
She was a magical beast but that didn't mean she couldn't learn techniques. She was even capable of learning a few other Laws as long as it was related to her original law.
After concealing herself, she encompassed them with her icy flames and killed them without a problem, thanks to Isabella provoking them with insults and delaying their actions.
"You look like you're scared that my husband is going to blame you. Relax~"