Despite the animosity between Rodrick and Greg (which I argue is largely indicative of a normal sibling relationship, even when Greg’s sociopathic tendencies are taken into account), Greg Heffley secretly idolises and aligns himself with Rodrick. This is demonstrated largely through the drawing style, with Rodrick, Greg, and their father being drawn with identical features. Frank Heffley clearly holds expectations for his sons, usually such that align with the traditional ideals of masculinity. Greg internalises these expectations despite often failing to meet them. Despite this, he depicts himself similarly to his father, indicating admiration. There is nuance to this regarding Frank’s abusive nature, but that’s for another time. Now, it could be argued that they are drawn alike due to a family resemblance, which is wholly untrue. Extended family aside, Susan and Manny show this quite clearly. Greg neither feels kinship nor respect towards these two characters, thus they are drawn without any similarities to Greg. This is particularly true with Manny, whom Greg often feels vindicated by, and therefore draws in an incredibly unflattering manner. Secondhand accounts prove that Manny isn't actually deformed as fuck, Greg merely perceives him as such. Furthermore, Greg also draws characters he feels positively towards, such as Holly Hills. Holly Hills looks exactly like Greg in a wig, which is also purportedly false, as she is objectively attractive and Greg is not. This solidifies the fact that Greg's illustrations are not objective, rather a manifestation of his own psyche. So where does Rodrick come in? Rodrick is also a disappointment in Frank's eyes, but unlike Greg, he does not attempt to please his father. For this reason, it is extremely unlikely Rodrick's illustration is based solely on Frank. He is sure of himself and content with being a loser. Greg admires this, and wishes to emulate it, therefore portrays them as similar. Rodrick represents to Greg what he could be if he overcame his fear of Frank.
