Kappa

Overview

Kappa ( 河童, meaning "water child") are, as mentioned, a type of water spirit youkai found in Japanese folklore. Often depicted as a turtle-shelled humanoid with a bald, depressed head ringed with hair and a waterfowl's beak, they were said to suck the blood from victims in the water through their anus, sometimes pulling their liver out in the process. However, like so many mythical beings they evolved drastically over time; they became much more moderated in depictions and actions, sometimes even going so far as to become friends with humans or at least help in some situations. It is said that whenever one should meet a kappa, if you need to escape you must bow to them; they are incredibly polite for whatever reason and will bow back. The top of their head is full of water and should they spill this water they will become weak and powerless, and thus easily escaped. They are also incredibly fond of cucumbers and sumo wrestling.  
 
In some regions of Japan they are said to transform with the seasons and become land-borne creatures.  

Specific Roles in Games

Game	Role	Image
Animal Crossing Series	In Animal crossing a Kappa appears as Kapp'n. Kapp'n is the driver of various types of transports in the Animal Crossing series. Deep down Kapp'n is a sailor despite also piloting other forms of transportation. Kapp'n is well known for his amusing sea shanties.   Role in each Animal Crossing Game:   Animal Crossing - Kapp'n appears when the player uses a Game Boy Advance Link Cable as the sailor who sails the player to the island. Animal Crossing: Wild World - In Wild World Kapp'n takes the place of Rover as the first character the player interacts with and is responsible for having the player choose a name for them self and their town. Kapp'n is also sometimes in "The Roost." Animal Crossing: City Folk - In City Folk Kapp'n is the bus driver which takes the player to their new town. Kapp'n is also the bus driver when the player takes the bus into the city. Like in Wild World, Kapp'n will also appear in "The Roost."
Ragnarok Online	In Ragnarok Online the Kappa is one of the monsters, or "mobs" in the game under the name Kapha. The Kapha appears one map north of the city "Amatsu."    Kapha Item Drops:   Aloe Leaflet Ment Loner's Guitar Cyfar Yellow Plate Jitte [1] Huuma Calm Mind [2] Kapha Card
Touhou 10 - Mountain of Faith	In Mountain of Faith, the shy river kappa Nitori tries to get the heroine to leave the dangerous Youkai Mountain, although she fails and is defeated.  Even though Nitori attacks the heroine, she is friendly to humans, and only wants to help them.  In the Touhou universe, kappa excel at engineering.