[The response comes so quickly that Diavolo doubts its sincerity, but he can't fault Doppio for his eagerness.]

The beast was much larger than you. Its teeth were strong enough to... to take off my head. But, Doppio, the similarities are striking enough that even I came to the conclusion that it must be you, and I know you better than anyone else. He can't be faulted for being mistaken, especially if that is the intention here.

[He paces further into the apartment, into the kitchen where he fixes himself a glass of juice. He talks at a low volume while he walks, as though he expects his voice to carry to Doppio regardless of his position.]

I've spoken to him briefly. If he's as invested in the actions of the monsters here as he he seems, he may be a valuable asset to us in the future. But if he's already suspicious of you... I think it would be best for us to keep a safe distance from him for now.

[Then he settles in a chair with the drink and leans forward, resting his chin against a hand deep in thought. Multiple potential explanations still roll around in his brain and no single one has stuck out as the most obvious yet.]

Do you remember when he was attacked? Did he tell you any of the details?