Of you're going to do this as serious (and not just over the top comedy) then you should limit the selection of character to those that might possibly fit in with the basic Ranma universe.
KOSMOS, for example, might be a bit hard to pull into the storyline. Same goes for, say Naruto, One Piece et al.
Also, be careful of pulling in characters with too much baggage. Again, for a serious story you want the story to mainly be about Ranma and Ryouga's fight and the other Stars of Destiny exist merely to supplement that plot (and the meta-plot of the Runic Cycle of Conflict effecting "Anime Earth"). In other words, I'd avoid Belldandy because her existence (and what it means) might overshadow the rest of the plot (this was the same reason we avoided Ah! Megami-sama in Hybrid Theory). Similarly, you might want to avoid Shaman King because of its metaphysical implications. Series like Noir face the opposite problem the character in it are just too LOW key.
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KOSMOS, for example, might be a bit hard to pull into the storyline. Same goes for, say Naruto, One Piece et al.
Also, be careful of pulling in characters with too much baggage. Again, for a serious story you want the story to mainly be about Ranma and Ryouga's fight and the other Stars of Destiny exist merely to supplement that plot (and the meta-plot of the Runic Cycle of Conflict effecting "Anime Earth"). In other words, I'd avoid Belldandy because her existence (and what it means) might overshadow the rest of the plot (this was the same reason we avoided Ah! Megami-sama in Hybrid Theory). Similarly, you might want to avoid Shaman King because of its metaphysical implications. Series like Noir face the opposite problem the character in it are just too LOW key.
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