Was Kroger the main character in this film?

The film was sponsored more or less by National Lampoon. In the 70s there was a fictitious editor at National Lampoon named Larry Kroger and they would feature him in little stories about how he was in high school and stuff like that. So they further fleshed out his character in Animal House.

The story is more or less told through his eyes although there were some famous scenes he wasn't in like Bluto climbing the ladder to look at Mandy in her sorority room and the time when Otter got beat up in the hotel room after Babbs says Mandy is waiting for him there and he finds all the guys from the other fraternity and Neidermeyer waiting for him.

For me one of the funniest scenes in the movie happens when Pinto, Boon, and Katy visit Professor Jennings and he smokes pot with them. "Do you mean one little atom in my fingernail could be ..." Jennings: "One tiny little universe!" And Pinto asks to buy some pot from him after that.

Thomas Hulce is an incredible actor as was also seen in Amadeus seven years later. Animal House might not have worked so well if they chose another actor for his role of Larry Kroger/Pinto.

I think he starts out as the main character for the beginning but as the movie goes on Otter takes the main character position

You'll have to decide for yourself if this is a film whose narrative is dominated by any one character, or if it is an ensemble film, employing a cast of complementary and contrasting characters who each contribute something to the plot, and whose collective experiences forms the narrative of this film.

I think it’s more of an ensemble rather than dominated by a leading role. It’d be interesting to know which characters get more screen time, but man do a lot them (Pinto, Flounder, Boone, Otter, Hoove, and Bluto, etc.) have side-splitting, relatable scenes.

Since Pinto and Flounder are characters we see from the beginning, we are introduced to the fraternity alongside them, our natural tendency is follow their stories with a “home base” feeling.

Pinto though, is more identifiable than Flounder perhaps because he is the Everyman.

Kind of reminded me of Caddyshack, in that it didn't really have much of a plot and didn't focus on one character.

If there were a main character, I'd have to go with Eric Stratton (Tim Matheson). He drove most of the plot.

I like to believe that Otter, Boon, and Hoover are the "main characters" (i.e. the de facto leads, since they have the strongest presence in terms of driving the plot forward) while Pinto and Flounder are the "audience perspective" characters, being the "newbies" to the Deltas.

The uptight frat dude from next door is the main character. He's given a challenge early in the movie by dean Wormer to get the Deltas thrown off campus. They're triumphant, but, like the blue people in Avatar, the Deltas get their revenge.