He is revealed later in the series to be Charlie's cousin.

However it is revealed later on in the series that he has strong feelings for Amelie.

It is revealed early in the series that she had been overweight while growing up.

Beyond that, not much was revealed about the castle's origins in the original series.

Rachel's decision, and David's ultimate fate, were never revealed in the series.

His female partner is Agent 99, whose real name is never revealed in the series.

Diabolik's true name had never been revealed in the series, and he doesn't know it himself.

These tidbits were revealed in the animated series and both films.

His formal birth name is not revealed in the series.

No more of her backstory is revealed in the series.