I wonder if Diavolo knows the requiem arrow was one of the ones he sold. He could've had the arrow this whole time. Just imagine him realizing this, or rather, recognizing it was true the whole time. Fate never meant for him to have it.
Which is a pantshittingly ignorant way to approach such a situation. Has thing, to in pain to use thing, no one believes thing works, not using thing will result in the RIsk Board going full nonsense mode - obviously he was unaware he had the thing he could not use dueto decades of self hate from a notorious rage a holic and his lesbian side kick who probably cheated on her girlfriend as often as pawsible. Yeah, that's the definition of fate, no need to double check that. Forsooth, it is said there is a prison in which no light may ever shine without screams of "Opie the faglord of Gayburg."