My proof is:

Um. I don't really have proof, but read Moon Rising. At the part where Peril gets to Jade Mountain, Clay says he wants her there.

that is my attempt at cleril proof.

also, pertle is not happening. first of all, turtlejou or turtljou: I have proof. You will see.

besides, Turtle can't touch Peril. And they're just friends.

Now I have proof, because I read Darkness of Dragons. Darkness of Dragons is one of the books I (sadly) don't have, but in the epilogue it Clay says:

"You have friends now. You have me." Like Clay is thinking 'I'm more than your friend.'