Terhi is Hondo's older sister, and it's safe to say that she does not approve of his habits, but it's not like she can stop him, he is an adult and not a hatchling anymore and as such makes his own decisions. He is a bit of a disgrace in her eyes. She cannot help but still care for him, even if it is only a little bit.
She came to the clan when she no longer wanted to remain with her home clan. Her friends had all gone away and had lost contact with her. When she heard of Hondo's acceptance into a clan she got into contact with him. She knew that he was her only contact with a leader of a different clan. Hondo had told her of the clan and when she came into contact with them, she found that they liked her intelligence.
She may not be as cold as other ice dragons can be, but she is rather reserved. She tends to come off as a bit snobby due to her intellect when combined with her reserved nature. However once a dragon gets passed that first impression, they'll find that she's gentle, but a bit shy.
She has an excellent memory, and as such works as the clan's librarian. She knows where every tome, novel, or scroll is. While her personality might be a bit off-putting, she is never rude, she might be stern if a dragon hadn't returned a book, but she wouldn't be mean to them.