As soon as the words leave your mouth, you realize that that was a stupid question. You already know why her hair is green. It's because the year she arrived, there were a lot of blonde girls in her group. She wanted to stand out, so she asked someone for some hair dye. Sure, it was green hair dye, but it was certainly different.

Turns out, she liked it that way, and her hair's been green ever since.

But Kaira doesn't dignify your question with that answer. She just stands there.

"I know, stupid question!" you say, and try to think of a different one.

"Mero, I'm sorry, but I really don't have time for this. I have a cold, and I should be resting right now. Okay?"

"...Fine."

Now what?
Go take a nap. You can't think of anything else to do.