@cherokeemoon my thoughts exactly (well, you forgot "actual").
@Raunix We still haven't determined if all of them are clones. Remember, the "real" prince may have died and these "clones" could all in fact be means by which "the good doctor" is using to advance his science as well as continue efforts to make an immortal or other related entity. We don't know for sure by any means yet, but my prediction is that we could be dealing with a situation so ilar to Cadmus and related plot twists in
Young Justice.
It would make sense that either the prince died and these are all clones, or if they are means by which Yuri can continue conducting his research. We don't know for sure, but likely Yuri did some major nonsense involving otherworldly magic and nafarious antics. Think
FFVII over here.