Ciel has one hell of a butler: a demon, bound by a contract to serve Ciel until his revenge is complete. Ciel serves the queen in rooting out the unnatural and unwholesome in Victorian England, counting on his butler as an ace. When the revenge is complete though, Ciel’s soul will be forfeit.
The inevitable death and fatalistic themes make this series dark, oppressive and enormously fun. Let’s be honest, an awesome bad guy is more fun to watch than some preachy virtuous kid. This series just gets more ridiculous and enjoyable.
The second season shakes it up a bit. It’s not quite as good, but it is a necessary end.