To the best of my knowledge all such claims, "Fork tailed devil", "Whistling Death", "Whispering Death", and so on were all coined by Allied media. I can't imagine a German pilot seriously calling the P-38 a "Fork Tailed Devil", nor can I seriously imagine a Japanese soldier calling a Beaufighter "Whispering Death". I think such claims served the dual purpose of making our equipment sound like the enemy feared it and at the same time debasing the enemy to a primitive mental level that would use such terms.