Clayface is an interesting possibility as he could also be part of the storyline that leads to the introduction of everybody's favourite psychotic clown. That is if as rumoured the producers favour the stand-up comic origin, inspired by The Killing Joke. It all depends upon how the interconnected strands of the series play out, but using the a combination of the Basil Karlo and Matt Hagen origins of Clayface being an actor (the approach taken by Batman: The Animated Series), we have the possibility of establishing a theatrical-based storyline which could also offer a fitting backdrop for the Joker's entrance. During the height of Batman's career Karlo/Hagen is an established actor, but in the Gotham version he could be a jobbing actor, treading the boards and trying to establish a name for himself. Skewing even younger, he could even be a dramatic arts student at Gotham Conservatoire. If he is a student then he's likely to have a room mate, possibly a fellow aspiring performer, but one with designs on making it on the comedy circuit.