Before I begin this seven-part analysis, I'll just preface it with a couple of points:

The Joker/Harley relationship underwent a very clear evolution in the DCAU world. However, the reasons for this are unknown and could be anyone of the following:

- A natural, subconscious progression on the part of the varying writers as others besides Paul Dini contributed their own elements and Dini himself refined his ideas on the characters and their relationship
- A conscious attempt to tone down and soften it either because of potential disapproval or because the creative team themselves were uncomfortable with its more abusive aspects (especially as Harley became a favourite character of many)
- A conscious effort to develop and expand on the relationship and emotionally further both characters, particularly The Joker and how he came to have an emotional attachment to Harley


Whatever the reason/s, the relationship definitely changed over the years, becoming more and more complex, multi-layered and interactive.

Initially Harley was a one-off character, a homage to the 'henchwenches' of the old 60s Batman series. Paul Dini kept on using her and then the team began playing with the idea of Harley being really obsessed with Joker, and developing it from there.

Therefore the earlier episodes of B:TAS show us quite a different dynamic, enough that it ultimately really adds to the character progression and the way they relate to each other.

As such, what we actually see with Joker and Harley's relationship is quite unusual for a kids' animated series: a long-term, naturally developing relationship between two major villains. It gives the relationship an even greater sense of authenticity and makes it quite unique in the world of cartoons and comic books, not least because of its abusive elements and Dominant/submissive dynamics.

Although the relationship with its accompanying 'Mad Love' background was not established from the get-go, nonetheless the canon eventually tells us Harley is around because she's Joker's obsessed ex-doctor. So even though the first few episodes don't indicate this obsession as clearly as some of the later episodes do, we have to assume she's already madly, passionately in love.

So what we see most in the evolution of this relationship is how Joker himself comes to be an active participant in it, and how his feelings over time very clearly grow - from seeing Harley as a useful lackey and adoring minion to regarding her as his girlfriend and partner. That this back story wasn't provided until further down the line actually makes for an even more realistic progression in the relationship from the perspective of Joker's own investment in it, so it ends up working all the more.

This article is an episode-by-episode analysis of how the relationship evolved over time. If you're unfamiliar with BDSM and D/s, power-exchange relationships, Wikipedia has some pretty good info on the subject.

PART ONE: The Henchwench
PART TWO: Possessed and Obsessed
PART THREE: George and Gracie from Hell
PART FOUR: Saving Grace
PART FIVE: Two of a Kind
PART SIX: The Ha-Happy Couple
PART SEVEN: Twisted Domesticity