Why is Justin in Secret of Nimh So Hot?

Justin is the Captain of the Guard in Secret of Nimh (movie) and a main character in Mrs. Frisby and the Rats of NIMH (book). He greets Mrs. Frisby, jokes with Mr. Ages, defends Nicodemus, and--in the movie--confronts the villain. 

He is a rat. 

He is an animated rat. 

Why is he so hot? 

There are two points here: one, as Wall-E shows, animated characters can be entirely personable.The beauty of a body in motion can be conveyed with pixels. Personality comes through body language, expression, and voice.

The second issue goes beyond the movie. Justin is a main character in both the book and the movie. He potentially sacrifices himself. In the sequels, written by Robert O'Brien's daughter, Justin has survived, which I find entirely plausible, namely because I don't think NIMH would kill the rats to begin with, whatever the lab told the farmer. In the sequel, a young character has a crush on Justin despite him being engaged. 

In the original book, Mrs. Frisby notes that Justin is handsome with "easy confidence." Multiple characters, including the children, note that he is nice. Justin was in NIMH and Nicodemus's descriptions make clear that Justin has always been alert, clever, curious, and reliable with a non-groveling deference to Nicodemus.  

In the book and the movie, Justin is the one Mrs. F(B)risby automatically trusts and turns to.

In other words, the print Justin is as attractive as the animated Justin. When I was younger, I was--like many readers--upset at Justin's potential death. Readers get attached. 

The loveliness of Justin is his humor coupled with his nobility. Consider the remarkable and touching goofiness of Wall-E that translates into pure noble action. Consider the utter coolness of a very different character, Saitama (sort of different), who looks like the guy hanging out behind the convenience store until he decides that a certain course of action is merited. 

Justin is sweet-tempered and heroic. A lethal romantic hero combination!