The Unblemished One.

Dyon had felt it, her frail body shredding to pieces in an instant. He had thought that she was dead, that he would never see her again. But he would have never guessed that Luna was a Heaven's Child… It was impossible for her to die an unnatural death even if she wanted to… 

[You're basically saying that my best friend has his best use as a pure-bred stallion…]

[He breaks the universe's rules. It's not difficult for him to have children, even with the most talented women in existence.]

[Oh please, how could the Heavens let its grand children die? Until they're birthed, Eli's children also have Heaven's Love. Afterwards though, they will be normal people. Well, normal and overly talented people.]

Words from the conversation he had with his grand teacher hit Dyon like a ton of bricks.