Malvin & Malcolm are the twin sons of Aunt Gretchen, cousins to Greg, Rodrick and Manny, and the nephews of Susan, Veronica, Cakey and Audra. They are very wild and her mother kept them on child-leashes when they were small. They are very mischievous and while they did not interact much with Greg, it can be presumed they cared little for him, like when they scared Greg while he took a shower and then proceeded to take pictures of him naked.