"Small Wonder"

It was fate in itself that a caterpillar had made its residence among the funeral flowers placed for the late Rei, and Nagisa did not know if he could let go of such a miracle.

"Couldn't we keep it, for just a while longer?"

"You know that's not what he would have wanted."

And at the end of things, he had to agree. Because his friend would not have wanted to shield the world from beauty, the importance of such a small wonder like the jeweled butterfly.

So Nagisa released it, in the anterior of Rei's grave, into the world.

AN) I seriously doubt Rei is going to die in the next episode, but hey, you never know.