Cadin is a cicada Yo-kai with a pale yellow, semi-egg-shaped body with a dark green abdomen, a pair of round eyes with large pupils and square, angry-looking, light brownish eyebrows, and a flat crown covered by a goldish vertex, this vertex then connects to a similarly-colored clypeus, which then connects to a rostrum which matches the color of his eyebrows. He has 6 limbs in total, 4 arms and 2 legs, all of which are a beaver color, he also has two of folded most of the time. He has a pair of light blue, semi-translucent wings on his back. He wears a pear-colored, sleeveless kimono tied with a purple obi and a pair of light brown zōri with purple thongs. Strapped to his obi sash, is a katana which he also grips in his right hand, it is sheathed in a red saya and has a purple tsuka. Cadin has a habit of falling asleep, and after waking up, he has only one week until he falls asleep again. Cadin seems to show a moderate amount of swordsmanship, seeing as he knows how to use the katana strapped to his obi. He claims to practice "cicada ninjutsu", which the Medallium theorizes might be a "mastery of running away".
Cadin's design is based on a cicada, specifically the Japanese species called min-min zemi (Hyalessa maculaticollis), after its "min min" cry which is also Cadin's catchphrase. (Said species is also a catchable bug in the game, called Green Cicada in the US port.)
Cicadas are especially known for their courtship calls, which are particularly loud (up to 120 dB, one of the loudest in the animal kingdom) and usually performed at dusk to avoid the attention of predators. They're regarded as one of the symbols of summer, and in past ages, both them and crickets would be kept as pets for people to enjoy their singing. They also give their name to a type of ninja decoy techniques (typically removing one's overcoat and luring the enemy into striking it), called utsusemi no jutsu ("cicada skin technique").
Etymology
"Semimaru" combines semi (蝉,"cicada") with maru (丸), a suffix typical of boy names. It might also be a wordplay on Semimaru, famous poet and musician of the Heian period.
"Cadin" is derived from cicada.
In Spanish, "Ningarra" is the combination of the words ninja and cigarra ("cicada").
Trivia
Unlike how Jibanyan, Dismerelda, and Happierre were the first three Yo-kai Nate meets in the anime, Cadin is the first Yo-kai befriended by the player to fight Buhu.
In the E3 trailer for Yo-kai Watch, Cadin can be seen attacking, still using its Japanese voice. This was changed by the time the demo and final game were released.
