[Fish Sandwich]

Quote:

Originally Posted by Kurona

One of the great things about Rider to begin with is how most seasons are standalone stories that are all allowed to do their own thing and be wildly different from the last, and having the objective of each be having to deal with some edgy Evol Black Hole wannabe would quickly diminish that. Aruto's angst over his dead secretary is not capable of carrying a story for long.

To put this more charitably, I'd say Ark-One has a very particular relevance to Zero-One's story that would inherently be lost by slapping him in someone else's. In a series that spends a lot of time pontificating on the inherent good and/or evil of the human heart, and how that's reflected in their creations, it's rather poetic for the hero's own negative emotions to directly give birth to the final boss. It's maybe a lot less meaningful if he just starts popping up in random shows with none of that thematic weight.