Khloe Kardashian is returning fire after her ex-stepmom sued her for defamation -- claiming the woman married her dying father at his weakest moment ... when he could barely stand on his own two feet. Khloe filed the declaration in Ellen Pearson's lawsuit, describing her experience during Ellen…

Kim Kardashian's ex-stepmom Ellen Kardashian has just sued Kris Jenner and the Kardashian sisters for defamation, claiming the K-fam is on a mission to make her look like a bitter gold digger -- when they're the ones who should be ashamed of themselves. Ellen filed the suit against Kris, Kim,…