When the "silver age" of comics hit in the '50s, DC began toning down the evil side of Joker to market their books for children and to avoid strict censorship. The 1942 story "The Joker Walks the ...
the Joker seems utterly immune to the curse, because, as it turns out, he already has an entire host of demons living inside his head. DC Horror Presents #4 – Written By Patton Oswalt & Jordan ...