Nyeusi is a slender yet well-built coal-black skink with dark smoke markings on top. His underbelly is a dark crimson which transitions to a regular crimson at the bottom, topped off with four black claws. His eyes are light green with black pupils.
Not much is known about Nyeusi, although he has been described as the stealthiest skink. He is easily able to follow Rafiki and Makini without being detected. Nyeusi does not appear to speak, but his hisses can be understood by Shupavu.
When Ushari and Janja are trying to find out if it's possible to summon Scar, Ushari enlists the help of his friends, a group of skinks. Intrigued, Shupavu summons Nyeusi and orders him to follow Makini and Rafiki, to see where they are heading. He slithers away and follows them to the entrance of The Lair of the Lion Guard, before returning to gather Shupavu and Ushari. Ushari questions him when he arrives, and Nyeusi hisses in confirmation. Shupavu and Nyeusi then leave Ushari to his business.
Later, Nyeusi spies on Kiara and Makini from atop a tree.
While Nyeusi listens to Scar's latest plan, Shupavu notices an intruder, Kinyonga. He and the rest of the skinks pursue her under Shupavu's lead. Nyeusi and Nyata are sent to capture the chameleon using their speed, but Kinyonga uses her tongue to grasp Nyeusi's leg and trip Nyata in the process.
They later corner Kinyonga at the end of a canyon, but before they can reach her, the Lion Guard reveal themselves, having used camoflauge to conceal their presence. Nyata and the rest of the skinks make a hasty retreat.