Yes, Arthur Fleck is dead. He's killed by a fellow inmate in Arkham, who is disappointed that Arthur disowned the Joker – the inmate feels let down. He's not named or identified, but ...

The death left a lasting impact on Xu who started suffering from insomnia, a weakened immune system, and frequent illnesses.

The woman, known only as Xu, made the extraordinary decision after the passing of her beloved Doberman, Joker.