Those who use a Youseiken may be possessed and transformed into its Kenbumajin.
The Youseiken have the ability to change their shapes, like shrinking down to small, knife-like sizes.
Due to their incredible power, most of the Youseiken have been sealed away since ancient times, only to be unsealed in times where their power might be needed to overcome great threats.
Yo-kai Watch Blasters 2
The Fudou Raimeiken is an item obtainable via QR Code in the game, which can only be equipped to Fudou Myouou.
In the Shadowside series, Haruya Sakami's goal is to collect all five of the Youseiken, which is supposed to awaken the full power of "the Princess" he is looking for. However, it later turns out that the Youseiken actually awoke Soranaki's full power when gathered together.
|Fudou Raimeiken (Japanese: フドウ雷鳴剣 Fudō Raimeiken)|
A dark blue Youseiken with a golden edge and triangular crossguard with a two-horned oni with fins on both side of it's head. The very thin oval part at the top of the crossguard has four small orbs in a straight vertical line from blue at the bottom to yellow, green and ending with red. Fudou Myouou is its Kenbumajin.
The Fudou Raimeiken is known to have been sealed away by the Enma Clan for generations, due to Fudou Myouou's uncontrollable power.
In the Shadowside series, Touma continues to use this occasionally to win battles, like in SS005 and SS010. It's stolen by Haruya in SS012, but recovered later in SS014. In said episode, Fukurou stabs himself in the wrist with it, turning him into Fudou Myouou Ja.
This Youseiken was the first ever revealed.
In the anime, and when playing with the toys, their chant is: (Japanese: 雷轟電撃！ フドウ雷鳴剣 Raigō Dengeki! Fudō Raimeiken) with Rock music.
|Suzaku Soutenzan (Japanese: スザク蒼天斬 Suzaku Sōtenzan)|
A purple Youseiken, it has a pinkish purple and gold coloration with a phoenix-based pattern on its handle, with pink spots in between the two phoenixes on the crossguard and each has one wing on both sides of the sword. What appears to be a pink gemstone can be seen on the handle, and can be split in two pieces and be used as twin blades. Its Kenbumajin is Suzaku.
In SS013, after the Fudou Raimeiken has been stolen by Haruya, Touma and the others set out to find this one. However, Suzaku no longer has it, and thus doesn't appear in the form of a Kenbumajin, but a Genjuu instead.
Its whereabouts were unknown, but was later found in SS021.
In the anime, and when playing with the toys, their chant is: (Japanese: 百花繚乱 スザク蒼天斬 Hyakkaryōran Suzaku Sōtenzan) with traditional Japan music.
|Ashura Gouenmaru (Japanese: アシュラ豪炎丸 Ashura Gōen-maru)|
A red Youseiken, the sword itself is golden in appearance, with a red blade with gold trims and about one inch wider than the other sword Youseiken, with a triple faced oni face with rounded ruby set above the head within its hilt. Its gold fiery handguards point sideways. The blade has a mirror-like, polished appearance compared to the hilt. There are eight red tines along its blade, and they range from simple outward pointing spikes to ones which have a slight outward curve to them, similar to a fiery pattern. its Kenbumajin is Ashura.
The whereabouts of its true owner are unknown. However concerning what happened in the 5th movie, it's possible that the Ashura Goenmaru is Ashura himself.
In the anime, and when playing with the toys, their chant is: (Japanese: 気炎万丈 アシュラ豪炎丸 Kienbanjō Ashura Gōenmaru) with normal music.
|Genbu Hotenfu (Japanese: ゲンブ法天斧 Genbu Hōtenfu)|
A green Youseiken that can double as an axe. The axe has a 6-foot long straight black hexagon patterned handle with a green emerald gem on the pommel, and what appears to be a golden snake coiled from the middle to the head. The axe head for each weapon has a rather standard shape for an axe head, though the toe and heel extend outward in a smooth curve. The axe head is gold with turtle shell shape and four red, green, yellow, and blue small orbs on equal sides, while the blade is golden. Also, on the top handle sticking out of the axe heads' middle is an emerald crystal. It's Kenbumajin is Genbu.
In SS031, the Yo-kai Detective Team travel to the Yo-kai World, where the battle Genbu and receive the Genbu Hotenfu.
In the anime, and when playing with the toys, their chant is: (Japanese: 明鏡止水 ゲンブ法典斧 Meikyōshisui Genbu Hōtenfu) with dance music
|Byakko Daireisou (Japanese: ビャッコ大霊槍 Byakko Daireisou)|
A light blue Youseiken that doubles as a Karigata Yari, a light blue bladed yari with two side gold blades pointing down flat polished with a tiger in the middle with gold fur flaring upwards on both sides while the bottom tip has a light blue diamond in the middle. It's Kenbumajin is Byakko
In SS045, the Yo-kai Detective Team travel to Reiken Forest and only Touma and Haruya are able to enter Byakko's lair, where the battle Byakko and receive the Byakko Daireisou.
In the anime, and when playing with the toys, their chant is: (Japanese: 疾風迅雷 ビャッコ大霊槍 Shippūjinrai Byakko Daireisou) with Jazz music.
In Real Life
After its debut in the anime, real-life replicas of the Fudou Raimeiken started being released in Japan, with the remaining Youseiken starting to follow.
- As of SS045, Touma Tsukinami is in possession of all the Youseiken. In SS049, Touma gives the Ashura Gouenmaru back to Shutendoji.
- It is currently unknown as to how the Youseiken are essential to Shuka's Awakening. However in SS045, the mural depicting the role of the youseiken in Shuka's awakening was actually a corruption done by Soranaki. Later in the following episode, it turns out that gathering the Youseiken awakens Soranaki's true power.
- When inserting the Enma Blade & Jaou Ken Youseiken from the DX Yami Enma Agito to the DX Yo-kai Watch Orge, their chant is: