Roughraff

Gurerurin (グレるりん) is a Goketsu-class Yo-kai ranked E. According to the Yokai Encyclopedia, "A yokai who's sole-mission in life seems to be to stir up trouble. He can turn even the most well-behaved child to a life of debauchery."

Appearance
Gurerurin is a green-skinned, lizard-like yokai with a short tail, large orange claws on his feet, a fairly muscular build, a pointed, curved mouth, a long red tongue, and orange markings surrounding his eyes and within his inner-ears. His most notable trait is his long orange pompadour, giving him the appearance of a Japanese high school delinquent. He wears blue pants and white gauze around his waist.

Personality
Matching his delinquent-like appearance, Gurerurin behaves in a very similar manner; he has little respect for others and tries to solve problems in a rough manner. In the anime, he attempted to mug Komasan, referring to him as a "hillbilly". When summoned by Keita for the first time, he answered in a noticeably rude way of talking.

In spite of his negative qualities, he is able to develop respect for certain people, such as Jinmenken after their fist brawl; Yokodori, after a pick-pocketing contest, striking an odd friendship; and Aniki. His methods of rebellious behavior tend to be on the tame and petty side, these attributes transfer into those he possesses.

Gurerurin has an odd phobia of hot waters, as seen when summoned by Keita to confront Nobosetonman.

Keita
Gurerurin is Keita's usual choice when he needs a tough guy; when first summoned, Gurerurin answered him in a rough tone of talking. After befriending Yokodori, he bluntly said Keita to not disturb him when causing mischief with the bird Yo-Kai.

Jinmenken
Gurerurin quickly grew to respect Jinmenken after they'd battled, acknowledging his strength.

Yokodori
Gurerurin forged a singular friendship with Yokodori after he and the bird Yo-Kai continuously robbed one another of their belongings. After Yokodori befriended Keita, he and Gurerurin left to hang out.

Aniki
Gurerurin, alongside other yokai, fell to Aniki's 'Cool big bro'-like charms.

Abilities and Powers
Gurerurin's most notable ability revolves around his possession; he can bring out the rudeness of the people he possesses, causing them to act as delinquents. The effects do not dispel until Gurerurin is defeated.

Gurerurin is also very fast, when striking a motorbike-driving-like pose and running in high speeds when chased.

Revenge- an attack that deals half the damage taken on by the opponent's attack right back onto the opponent. However, it will not activate if Gurerurin's HP is knocked down to 0, if the opponent's attack is absorption-based, or during an opponent's death blow. The "Shark Skin" skill has the same effect as this.

History
Gurerurin debuts in episode 3, when it is revealed that he is the cause of Kanchi's sudden turn of personality. When confronted by Keita and Whisper, he flees from the scene without dispelling Kanchi of his possession, causing Keita to chase him to defeat him to turn Kanchi back to normal. After finally catching him up, Keita summons Jibanyan to battle Gurerurin, but quickly falls victim to his possession and becomes Warunyan. Keita resorts to summon Jinmenken and after encouraging him to confront Gurerurin, the two engage in a brawl. After a long battle, it ends in a draw, the two Yo-kai lay on the ground, bruised and laughing. Gurerurin acknowledges Jinmenken's strength and shakes hands with him. Sometime after that, Gurerurin gives Keita his Yo-kai Medal.