The eponymous miracle baby himself, Bio Miracle Bokutte Upa was the only game in its series but the little scamp was given a second wind by Parodius.
Now here begins a problem I have with some of the guest characters. Original characters Like Mambo, Koitsu and Michael have recolours as their second players and it's hard to argue with that since they were made for these games to begin with. Guest characters like Upa and Kid Dracula also got recolours, essentially making up new characters attached to another series to which they don't really belong. I never understood this. When Goemon appeared in Fantastic Parodius on the SNES he was accompanied by Ebisumaru, the natural second player for him. For Upa (and also Kid Dracula) no effort was (apparently) made to find a suitable existing character so recolours were simply fabricated.
This is less of an issue for Upa because, according to sources, Rupa is his younger sister and since he only had one game it's feasible that a second baby was born after its conclusion and as babies it's feasible that they would look incredibly similar.
Despite this I borrowed the design from one of the kidnapped babies in the instruction manual, just to make Rupa look a little more distinguished.