Excellent guess both of you, but not the bright Adolin. I hadn't thought of him as matching these clues.
Not the most sane Herald Ishar.
1. This character is very curious.
2. This character spent a lot of time with another and didn't know it.
3. This character does not have a nahel bond, but tried for one in an unorthodox way.
4. This character tries their best to imitate others' behavior and appearance.