Since his first appearance in 1994, King K. Rool has been Donkey Kong's arch nemesis in the Donkey Kong Country series and beyond. His name is meant to resemble the word "cruel" and describes his hatred for the Kongs, as well as the iron fist with which he rules his minions, the Kremlings. Although most often recognized by his red cape and golden crown from Donkey Kong Country, he has also shown a tendency to reinvent himself following a defeat, donning new wardrobe and weaponry, and order his army to do the same. Additionally, most attacks at the Kongs have been less about obtaining Bananas and more about exacting revenge for all the losses.
Donkey Kong Country Series
In his debut, King K. Rool ordered his Kremling army to steal the legendary hoard of bananas hidden beneath Donkey Kong's treehouse. K. Rool himself does not appear until the final boss fight of the game. This fight takes place on the vessel K. Rool used to reach the island, The Gangplank Galleon, which has been anchored off its coast. After the player scores so many hits against the king, he appears to be defeated and credits begin to roll. Suddenly he hops back to his feet and the fight begins anew. Finally he is truly bested by Donkey and Diddy Kong and the banana hoard is recovered.
In Donkey Kong Land, K. Rool ordered the banana hoard stolen again, and brought it through jungles, oceans, and mountains before reaching Big Ape City, where DK and Diddy stopped him and retrieved their hoard.
In Donkey Kong Country 2: Diddy's Kong Quest, K. Rool returns using the disguise of a pirate captain and a fitting alias, "Kaptain K. Rool." He kidnaps Donkey Kong in hopes of a trade, possession of the banana hoard for Donkey Kong's safety. However protagonists Diddy and Dixie Kong refuse his demands and attempt to rescue DK. Upon reaching the tower where he is being held and seemingly beating the game, Donkey Kong is lifted to K. Rool's airship, the Flying Krock, revealing a last set of stages.
In the boss battle itself, K. Rool uses his blunderbuss to shoot cannonballs at the Kongs. Throughout the battle, Donkey Kong appears at the top of the screen from time to time, trying to break free from his bonds. When the player does enough damage, Donkey Kong finally breaks free and delivers a huge uppercut to K. Rool, sending him through the windshield and all the way down to the murky water below. The game could be considered beaten at this point, but a Lost World exists wherein the player can face Kaptain K. Rool a second time after completing another series of levels.
For the final installment in the series, Donkey Kong Country 3: Dixie Kong's Double Trouble!, K. Rool has supposedly been defeated for good and a robot has replaced him as leader of the Kremlings. When Donkey and Diddy Kong never return from their vacation in the Northern Kremisphere, foul play is suspected. Dixie and Kiddy Kong then attempt to discover their whereabouts, and they are finally lead to the Kastle KAOS. After the two find and defeat this robot, a Wizard of Oz like twist occurs and it is revealed that K. Rool was actually "the man behind the curtain" the whole time. Using yet another false identity, Baron K. Roolenstein, he attempts to fight the duo with his helicopter device and electricity attacks. Upon being defeated, Donkey and Diddy Kong are rescued from their prison, the inner workings of the previously defeated robot.
As in Diddy's Kong Quest, a second battle can take place against K. Rool if the player finds a large amount of collectibles and makes it through an optional set of levels similar to The Lost World.
After that, K. Rool, still going by K. Roolenstein, vied for the Lost World in Donkey Kong Land III.
Beyond the Country Series
K Rool has made several appearances since the DKC series, though he's never been quite as into reinventing himself or his armies after DK64, in which he settled on iconic designs for himself and his minion crew, outside of a Boxing outfit for the final boss fight. Since then he's been featured as a trophy in the Smash Bros franchise, and made an appearance in Mario Super Sluggers dressed like a Mayan.
In addition, K. Rool has served as the villain in PAON's DK King of Swing and DK Jungle Climber, both of which revolve around swinging using the shoulder buttons. In the first, he stole the medals that the Kongs intended to use in a small tournament, his most petty villainous act. Conversely, in DK Jungle Climber he tries to steal the banana shaped hyperdrives of a passing alien and hand them out at random to his best men, which is notable as his only notorious deed where the Kong family were not the intended victims.
K. Rool did not return in Donkey Kong Country Returns or its sequel Donkey Kong Country Tropical Freeze.
K. Rool likes to travel with class, and tends towards having monumentally sized vehicles, his first being the pirate ship The Gangplank Galleon, which served as the stage of the final boss fight in DKC and as the first world in DKC2 and DKL2. Later though, he's more often than not flying a crocodile shaped airship, of which he's had 4.
The pirate ship that was docked at DK Island in DKC, this is where K. Rool was fought for the first time. Later, it would become a full world in the sequel.
The Flying Kroc
K. Rool's first airship, it was primarily used as an escape vehicle once Diddy and Dixie breached his stronghold, K. Rool's Keep. However, the ship ended up getting tangled in the overgrown giant brambles and the pair was able to catch up and retrieve DK by fighting K. Rool in the bridge.
K. Rool's one and only submarine, this was used in DKC3 primarily to hide from plain site under the waters of Krematoa. However, Boomer Bear, with the help of Dixie and Kiddy, managed to force the Knautilus out from hiding. Following being revealed, K. Rool was fought once more, this time for a DK Coin.
At the end of DKC3, K. Rool stole Funky's hovercraft. However at that point the Kongs had freed the Mother Banana Bird, which chased K. Rool down and dropped a giant egg on him.
The King Kruizer II
The sequel to the Flying Kroc, the K. Kruizer II was an escape vehicle used towards the end of DK64 when the DK Crew disarmed K. Rool's Blast-O-Matic located in Hideout Helm. The vehicle soon found itself crashed at the gigantic hands of K. Lumsy, allowing the DK Crew the chance to finish the game.
The K. Kruizer III
The third in the line of Kremling designed airships captained by K. Rool, the K. Kruizer III was seen in DK: King of Swing, and served as the last world, providing 4 levels and a confrontation between DK and K. Rool.
A one man hovercraft made for K. Rool. He used it briefly in DK King of Swing to steal the Jungle Jam's medals. At the end of King of Swing, DK stole it to make the trip home easier.
The K. Kruizer IV
The latest in the K. Kruizer series, the K. Kruizer IV is the airship used in DK: Jungle Climber. Found high over tall tall island in space, this iteration is notable for being the only model that has reached space to date. It is likely that its development enabled the Kremlings to steal the Crystal Bananas DK: Jungle Climber focuses on.