Role in the series
The name "Dunder" is taken from the word "dunderhead," a dimwit who does not do many tasks right. Unlike his fellow Thembrian soldiers, however, Sgt. Dunder does not speak with a Slavic accent, which is interestingly also a trait of Colonel Spigot, both of whom are the two main Thembrians featured on the show. He is not so much an antagonist like Spigot, just a character who is extremely unlucky to have been born into the oppressive nation of Thembria and then been made to serve under an arrogant leader such as Colonel Spigot. Baloo and Kit's plots against the Thembrians usually avoid involving Dunder.
However, in one episode, Dunder is indirectly involved, as Kit puts together a plot to break Spigot, emotionally. After eavesdropping on a case where Spigot gives Dunder a dressing down for poor performance and orders Dunder "out of his sight," Kit then hacks into the intercom system and impersonates Spigot, yelling "Dunder, get in here now!" This causes Spigot to slowly lose his mind, as he wanted Dunder out, yet all the other Thembrian soldiers back up Dunder in saying that they, too, heard the order for Dunder to "get in [Spigot's] office, pronto".
Although Sergeant Dunder has many of the attributes of Disney villain underlings, such as not being very intelligent and being made to suffer at the hands of arrogant villains, he is at heart, a decent person, and a dedicated soldier. He does not bear any ill will towards Baloo, and will even go so far as to help Baloo when he sees there is a dangerous situation that could endanger everyone.
He is voiced by Lorenzo Music, who is best known on the Disney Channel for his role as Tummi Gummi in Disney's Adventures of the Gummi Bears, and for the role of the non-Disney animated characters Garfield the cat and Peter Venkman.