Dragonballs / coloured spheres

I know that the emperors/high kings have these in KUMITE mode but where do they actually come from??

Can you actually get a ball without steaing it? If so how?

 

No. Stealing them is the only way.

 

I'm not sure about the console, but there are a few ways to get them on the arcade. Of course, nobody knows of them, thye just appear out of nowhere. Times, that they've appeared:

Same dan-level fight
Card renewal (if your opponent is 2-dan or higher, and you win).
Of course, stealing them.