The Death Battle I know of is a YouTube channel wherein two hosts provide statistics about two characters from all sorts of franchises (some including anime; for example, an early one pitted Goku against Superman), then show an animation of how they postulate a fight between the two of them would go, then defend their assessment at the end.

The two hosts do kind of present in an anime fashion. I’m not sure how they make their animations, but they’re generally unique visual styles per episode, so depending which episode you see you might think different things about their genre.

I don’t know anything about the subreddit.