Uhm, no. Actually the VA of Koyomi is Rohan in Jojo's: Diamon is Unbreakable.
(at least in All-star battle).
As for that spoiler. It's an interesting turn of events to be sure.
Oh. I didn't look at his VA yet.
And I remember reading about that armor becoming important later on, but I stopped because of spoilers. Who would have guessed that when I wake up and check for news I would be clicking the same spoiler I avoided yesterday.