User blog comment:Cococrash11/Hollows breeds with humans/@comment-1432572-20100503211902

@Sata, we dont know if they were before they became hollows, but what we DO know is as hollows, they are brothers. Plus there has only ever been 1 Hollow to remember his life as a human (Shrieker) out of the thousands of low-class Hollows we've seen thus far, so the chances of Yylfordt and Szayel being brothers before death and actually remembering that fact is slim to non-existent.