The tweets attacked her personally, she explained in a blog post on Thursday, and celebrated the end of “Mockingbird.” “Mockingbird is canceled,” Cain had tweeted early last week. “But we need to make sure @Marvel makes room for more titles by women about women kicking ass.” She also tweeted out the cover of the last “Mockingbird” issue and encouraged followers to buy that issue and “send a message to @marvel that there’s room in comics for super her stories about grown-up women.