Donkey Kong (or D.K. for short or full name Donkey Kong the 3rd) is a gorilla that wears a red tie with his short name (D.K.). He fought Jumpman in 1981 in the first commercially successful video game called Donkey Kong, although later, he was stated to be Cranky Kong.
The current Donkey Kong is Cranky's grandson, the third generation in the Donkey Kong Lineage after his father Donkey Kong Jr, and first appeared in Donkey Kong Country as the main protagonist, along with his nephew/best friend Diddy Kong. He appears in some of SuperMarioGlitchy4's bloopers.
In The Wacky Wario Bros.: Wario's Treasure Hunting Time, he had a real gun.
In the same episode, Donkey Kong shoots anyone who steals his treasure.
That said, he hates Wario because he stole his treasure that time.
He is sometimes referred to as "The Dong," or "Master Dong" by Jeeves and pretty much everyone else. SMG4 and Kevin even call him this on their gaming channel. It is meant to be a satirical combination of his first and last name.
In Welcome To The Kushroom Mingdom when SMG3 is saying who each of his kingdom's inhabitants are in relation to the inhabitants of the Mushroom Kingdom, he gets to DK's replacement and says Konkey Dong instead of "Donkey Kong." This was probably intentional, due to the running joke of shipping his first and last name to create "the Dong."