The faint growls of Little Yin's rage only reached the guild guards because she allowed it. After her and her brother's existences were anchored in this timeline by their contract with Dyon, she could freely control these things as she pleased. She wanted these people to know that that attack was not a fluke, Clara was protected!
When one speaks of the battle bloodline of the Celestial Hamster, it's only really possible to mention it with vague generalizations. Even for the race themselves, the only thing that they were certain of was the fact that it only appeared within the royal lineage.
Little Yin herself wasn't entirely aware of just how she awoke, but she had a vague understanding. From her birth, until now, the range of emotions Little Yin had felt was limited. Much like a child who had yet to learn the pain and horror of the world, her small eyes were tinted by a rose color that hard to remove.