When it comes to the world of Artemis Fowl, the name of the game is intelligence. Magic is quite obviously a huge factor in the story but how smart those characters makes the story move forward. They perceive and understand things that most people don't, which is kind of important in their world.
Any fans of Artemis Fowl probably have a pretty good idea of who the smartest character is. But there the rest of the main characters fit in some surprising spots on that list. It's a group of quite intelligent people and mythical creatures.
Mulch Diggums
A career criminal, Mulch Diggums was a constant menace who loved tormenting the officers of LEPRecon. He particularly enjoyed messing with the always stern and serious Commander Root. Despite that, she still brought Mulch in to help with the rescue of Holly Short. He might have been a criminal but Mulch was still someone who would do the right thing when the chips were down.
It's not that he wasn't smart but he also wasn't the brightest guy in the movie. And being able to outsmart LEPRecon officers was a pretty low bar to get over in of proving one's intelligence.
Commander Root
As a commander in the Lower Elements Police Reconnaissance, aka LEPRecon, Root did not have time for anyone's shenanigans, least of all Artemis Fowl's. In particular, she needed everyone to stay on point when they went to rescue Holly Short from Fowl Manor.
Commander Root was an old-school law enforcement officer who was immediately in charge of whatever situation she stepped into. But her extreme distrust of modern technology tended to put her at a disadvantage. It's hard to say if it's because Root just didn't care enough to bother to learn how to use new technology or that she just didn't understand new technology.
Artemis Fowl Sr.
The fairy-folk of Artemis Fowl lived in a secretive world that was often under assault from a surprising number of angles. A wealthy human who was quite aware of the mystical realities that most people didn't know about, some fairy-folk viewed Artemis Fowl Sr. as a thief. In truth, he was one of their greatest allies, who worked to protect them and their history from those who would take advantage of them.
While he was incredibly capable on a number of levels, Artemis Fowl Sr. was a human of slightly average intelligence. Unlike his son, he wasn't an overwhelming genius who could outsmart anyone and understand everything
Domovoi "Dom" Butler
Living life the way Artemis Fowl Sr. did meant that there were a lot of people were after him. He needed a bodyguard, and no one could ask for better protection than Domovoi "Dom" Butler. His family had spent generations guarding the Fowl family. Even when Artemis Fowl Sr. disappeared, Dom stopped at nothing to rescue him.
Dom was intelligent, capable and a dangerous man when the moment called for it. Dom was still one of the most perceptive and noticed things that others missed, placing him in the middle of the pack.
Holly Short
A captain with LEPRecon, Holly Short was well versed in dealing with other characters like Commander Root, Foaly, and Mulch Diggums. What she wasn't as prepared for was dealing with Artemis Fowl Jr. and Dom Butler, who were working a parallel case to hers. What was interesting about this was her father was actually an associate of Artemis' father.
Holly was a smart, young captain with an indomitable will to overcome almost any situation. Like most individuals, Holly wasn't as intelligent as Artemis but she was a match for him in several other ways.
Juliet Butler
As the niece of Dom Butler, Juliet was already in the process of being prepared for the family business of protecting the Fowls. But she was extremely happy about that and was looking forward to the challenge of trying to keep Artemis Fowl Jr. alive.
Fearless and triple tough, Juliet had no issues stepping up to any challenge. That included the massive troll Briar Cudgeon unleashed on Fowl Manor. She was sharp as a tack and knew how to put those smarts to good use. Dom brought her in because he thought having a bodyguard the same age would get through to Artemis and Juliet successfully did that, a massive task to have accomplished.
Foaly
While the Lower Elements Police Reconnaissance was firmly rooted in the mystical foundations of the fairy-folk, they still needed to be able to access modern technology. The human world was changing around them and they had to keep up, regardless of what Commander Root thought. That's where Foaly, a centaur and the technical advisor to LEPrecon, came in.
Foaly was responsible for the development of much of the fairy world technology. As such, he was incredibly smart and well-versed in things a lot of fairy-folk simply did not want to understand. This was a big reason why Commander Root didn't like Foaly at all.
Artemis Fowl Jr.
At the core of the story was Artemis Fowl Jr., and not just because the movie was named after him. He was by far the smartest person in this world. Artemis absolutely destroyed every I.Q. test he took, making him one of the smartest people around. By age of ten, he had beaten the European chess champion in five moves, designed the Dublin Opera House, and cloned a goat.
But that intelligence came at a price. Artemis was arrogant, cold, and difficult to deal with. His only friend was Dom, though Juliet and Holly did make some serious inroads towards becoming closer with him. There are all kinds of intelligences, and though Artemis may have been lacking in some, his smarts are still overwhelmingly the sharpest.
