Uka Uka is the evil younger twin brother of Aku Aku. Uka Uka was created by Naughty Dog as a presence that was able to cause even Neo Cortex to cower in fear. He was voiced by Clancy Brown from 1998 to 2003, by Alex Fernandez in Crash Twinsanity, and by John DiMaggio in Crash of the Titans and Crash: Mind over Mutant. He is voiced by Ryūzaburō Ōtomo in the Japanese versions of his appearances up to Crash Twinsanity.
Several eons before the events of the series, Uka Uka was locked away by Aku Aku in an underground prison due to his malevolent nature. Several millennia after his incarceration, Uka Uka recruits Doctor Cortex to fulfill his desire to enslave humanity, only to have Doctor Cortex lose the Crystals and the Gems, and have his space station destroyed. The rubble of the ruined space station eventually crash-lands onto Earth, destroying the underground prison, and finally freeing Uka Uka. Upset with Cortex's failure to retrieve the Crystals and the Gems, Uka Uka recruits Doctor Nefarious Tropy, who has created the Time Twister, which will allow them to collect the Crystals and the Gems in their original places. And, since Cortex's failure also managed to set him free, Uka Uka still felt a sense of gratitude and generosity. When Crash intervenes and destroys the Time Twister, Uka Uka is trapped inside a time prison with Doctor Cortex and N. Tropy, who have been turned into infants. Uka Uka appears in Crash Team Racing as a tutor for the characters Cortex, N. Gin, Tiny, and Dingodile, giving them useful tips and tricks throughout the game. He also appears as a power-up during the races, protecting the said characters (along with Ripper Roo, Papu Papu, Komodo Joe, Pinstripe Potoroo and Doctor Nefarious Tropy) from all attacks and obstacles while giving them a speed boost. However, he cannot protect the characters from chasms and deep water. In Crash Bash, in order to resolve his constant fighting with Aku Aku, Uka Uka summons Cortex, Brio, Tiny, Dingodile, Koala Kong, and Rilla Roo as part of a contest between his players against Aku Aku. Uka Uka is later forced to relinquish Tiny and Dingodile to Aku Aku's team to even out the number of players between them.
In Crash Bandicoot: The Wrath of Cortex, Uka Uka scolds Cortex and the rest of the villains for their less-than-impressive evil productivity. Fed up with Cortex's incompetence, Uka Uka concludes that if global domination is to ever be achieved, Crash should be handled with personally. Deciding to use Cortex's new super-weapon to wipe out Crash Bandicoot, he revives the Elementals to act as the super-weapon's source of power and bring it to life. When Crash imprisons the Elementals, defeats the super-weapon, and brings it to their side, Uka Uka holds Cortex responsible and fires an energy blast at him out of anger, but in doing so causes their newly built space station to overload, forcing Cortex and Uka Uka to evacuate. Their escape pod lands in the depths of Antarctica, stranding them both on a sheet of ice. Uka Uka oversees the evil plots of both Neo Cortex and Nefarious Tropy in Crash Bandicoot: The Huge Adventure and Crash Bandicoot 2: N-Tranced respectively, becoming annoyed when both of them fail. Uka Uka reprises his role from Crash Team Racing in Crash Nitro Kart, giving useful advice and acting as a power-up for the characters Neo Cortex, N. Gin, Tiny Tiger and N. Tropy. In Crash Twinsanity, Uka Uka is freed from a wall of ice, but is enraged to see that Cortex has teamed up with Crash in order to defeat the Evil Twins, and transforms into an Ice Titan in order to kill both of them, considering that he still held a grudge against Cortex for his past failures. When he is defeated, Uka Uka attempts to flee, but Aku Aku stops him and tells him about the Evil Twins' plot to destroy the Earth. Opposed to the fact that someone else is trying to destroy the world (a job that he believes is his), Uka Uka temporarily teams up with his twin brother, only to be defeated alongside him by the Evil Twins' ability to warp reality.
Uka Uka has a cameo appearance in Crash Boom Bang! as a purchaseable power-up. In Crash of the Titans, Uka Uka teaches Doctor Cortex a new process called "Mojo mutations", which uses a magical substance known as Mojo to mutate any living creature into a loyal minion of Cortex. At the Temple of Zoom, Uka Uka leaves Doctor Cortex to destroy Crash and Aku Aku while he returns to the base with an enormous amount of stolen Mojo and Coco Bandicoot at tow. When Cortex fails to defeat Crash, Uka Uka becomes furious, and announces that he is replacing Doctor Cortex, much to the shock of his minions. In a lab on the island's giant tree, Uka Uka expresses his relief with Nina Cortex's higher competence, but begins to sense Aku Aku's presence nearby, and decides to stay in the lab and kill Crash Bandicoot himself. Uka Uka confronts Crash as the penultimate boss by using Doctor Cortex's Evolvo-Ray on himself, giving him a gargantuan body made from the tree's wood. When the Evolvo-Ray is destroyed, Uka Uka claims that he will have the last laugh, as Nina is about to launch the Doominator, threatening the existence of Wumpa Island. Uka Uka is absent in the Nintendo DS version of the game. In Crash: Mind over Mutant, Uka Uka is subdued and placed in a milking machine by Doctor Neo Cortex and Doctor Nitrus Brio so that he can be used as a source of the bad Mojo needed to control those using the mass-produced NV device. He is eventually freed by Crash and Aku Aku, and promises to take the two to Cortex's new space station if his magical bones are returned to him. When this task is completed, Uka Uka keeps his promise and warps Crash and Aku Aku to Cortex's space station as an act of vengeance against Cortex.
Read more about this topic: Characters Of Crash Bandicoot, Antagonists