Charlene was mildly offended at the idea that someone would even think she was a human, whether she looked mostly like one or not. She was no landwalker with their weak senses and inability to live under water. Nor did she want to be. So at what she imagined to be an insult, Charlene just dropped her hands and stuck her tongue out. There was a rude gesture that she had seen humans throw at one another, but she could not remember which finger it involved so she decided not to try using it in case she got it wrong. Then she turned her attention to smoothing out her hair, missing the silver sheen that she was so used to having there. It was still a nice color, true, but it was not as nice. No wonder people like Roxy went and added colors to their hair when they got bored with it being the way that it was. Charlene may have done that - oh, she was being asked what she was.
Explaining things was much easier when it was light out and she could write things out instead of having to do her best to mimic and motion with the hope that it would be understood. And did she really want to explain what she was? More than a handful of humans knew, that was true, and even a vampire did and had not brought her harm. But that was because she was in the water and that Bea had been afraid of the water for a reason that Charlene still did not fully understand. No one's actually hurt me because of it except for that one human, but she was different. These ones don't seem like that at all. She could not see weapons, past the fangs that she knew the vampire had, and nor did she really smell any extensive bits of metal. Just the alcohol. Glancing up, Charlene noted a light on top of a long post a little ways away and carefully got to her feet, stumbling only a little, so that she could move towards it. Pulling out her notebook and her favorite blue Sharpie, she drew out a sketch of herself and held it up. Mermaid! Much better than a vampire, I don't live off blood. Sure her sister had probably eaten someone earlier that day, but Nixie was not Charlene.
Then, just in case one of them wanted to know, she added a quick line underneath: 'You're drinking poison. It'll make you sick.'