Shady Kong is a Kong, appearing in Ultra DK. His exact connection to the kong family is unknown, although he and Lanky Kong used to be friends. He has a strong rivalry with Diddy Kong, and has vowed to kill him one day. Why he has this much anger towards him is unknown.
Although it appears that Lanky Kong is the main villain, Shady Kong is the actual main antagonist of Ultra DK. What exactly happens is unknown.