Karasuma is from another planet - it is a proven fact. This two evidences are more then enough.
So now I suggest you to discuss the important matter: what does his planet (were his most likely is a Prince) look like? Why is it important: because, in case Karasuma will really be leaving (but not to America - to his homeplanet) will Tenma follow him or not? If environment there is not good enough she may stay - and then Odou will get its' brilliant chance to win. But if thst planet will suit Tenma then Flag and Onigiri will preveil. So what do you think Karasuma's planet looks like?
(of course this whole thread is speculation so wright what yoiu want - as long as it is funny its' OK)