book 1: The Arcobaleno's death weapon

What if skull was a death weapon from DWMA and part of the eight shinigami legion. What if the arcobaleno, Vongola and others finds out about it. It takes place during the clown arc in soul eater and before the operation capture Baba Yaga arc.
I do not own katekyo hitman reborn nor soul eater by ANY means. Akira Amano is the creator for khr. Atsushi Ōkubo is the creator of soul eater.