This is just going by the manga, so I'm not going to waste anyone's time with the whole "#19 in Hell" thing.
We know that Android 8 came back after Buu blew up the Earth, and we're never really told what he is. Daizenshu #4 lists him as "Biomechanical" along with 17 and 18, but we dunno if he too is a modified human, or maybe like his inspiration he really is corpses sewn together.
That same Daizenshu lists 16 in the same section with 19 and 20, which is confusing to say the least, seeing as how 19 is also purely mechanical whereas 20 has a completely human brain and could no doubt come back. So that leaves it up in the air.
But my main reason for thinking this is just based upon the tone of the series. Arale is purely mechanical too, and I don't think Toriyama would have liked to kill Arale permanently when Buu blew up the Earth. She's too cute.
So please, think of Arale.
Thoughts? Holes in the theory?


