I don't own Senran Kagura or Kamen Rider and they belong to their respected owners.

"Calamity Strike," Desast says, a monster called a Megid created by combine three twisted versions of storybooks.

When Desast said those words, he leaps into the air and executes multiple magenta energy slashes with his sword, Grudge Dent while spinning as the slashes hit all the staff and students of Hanzo Academy.

"Everyone!" Asuka shouted arrived at the scene, to see her friends and classmates critically hurt by this monster. Her friends were down but still alive.

"Who are you?!" Asuka question.

"I'm Desast, and someone told me to test, you ninjas." Desast shrugged. "But I have to say I'm not impressed."

"We'll see about that!" Asuka holds up the small green book with an image of a green ninja upside down and in front of a yellow background and brought out to be a large green sword.

Sarutobi Ninja Den!

"It can't be…" Desast muttered, his eye locked on the green sword and book.

"A book about ninjas?" Ikaruga pondered.

"What was it called again?" Katsuragi asked.

"A Wonder Ride Book," Asuka answered. "It supposes to hold some kind of power from a story of a heroic ninja adventure," Asuka says.

Asuka then opens her Ride Book to the story page with the image of green shurikens.

Toaru kage ni shinobu wa shippu! Arayuru jutsu de iza sourou...

Asuka then closes it before she plugs it into the slot on Fuusouken Hayate's side before separating the sword.

Sou Tou Bundan!

A giant Wonder Ride Book of Ninja Den appeared behind Asuka as it flips open to a green ninja's arm.

"Henshin!" Asuka shouted.

Ichi no Te, Shu~ri~ken~! Ni no Te, Ni~tou~ryuu, Fuu~souken Hayate~!

Asuka then performs a diagonal 'X' slash that takes the form of a shuriken, before a cyclone from the Wonder Ride Book circles her and forms the armor, with the slashes forming the visor, completing the transformation while doing some slash maneuvers.

Hayate no Maki, Kouga Fuuton no Souken ga Shinsoku no Ninjitsu de Teki o Utsu!

Asuka's armor is green dominantly over the black suit beneath it as the armor covers her collar, chest, sidearms, thighs, and frontal legs. The only secondary color is a dash of yellow only on one armor piece per limb. Her helmet on the left side is in the shape of a shuriken while the left side is on the edges of two katana blades both sides green in color. This is Kamen Rider Kenzan!

Kenzan began attacking Desast with Fuusouken Hayate in Nitouryu Mode but the monster was pretty skilled with a sword.

"Who sent you?" Asuka asked.

"What makes you think I'll say?" Desast says as blocks an attack.

"Then I guess I'll have to force it out of you!" Asuka went for another attack.

"Heh, show me what you got," Desast mused as he kicks back Kenzan.

Desast then grabs her with his scarf and started pulling her in and when she was close enough, gave her a powerful slash knock her back.

Kenzan stumbles to the ground, "Itai, itai." She jumps back up and takes out another Wonder Ride Book.

Kobuta San Kyoudai!

She combines Fuusouken Hayate back to Ittouryu Mode.

Ittouryu!

She then scans the Ride Book into Fuusouken's slot before pressing the Hayate Trigger.

Kobuta San Kyoudai!

She summons the apparitions of 3 Little Pig Brothers.

"Let me show the power of Ninnin! Asuka exclaimed.

The 3 Little Pigs start building three separate brick walls to surrounding Desat while Kenzan runs around the walls with great speed confusing her enemy.

When Desat had his back from the wall Kenzan was hiding the brick wall revolves and did a surprise attack by slashing his back making him tumble forward.

Then she inserted another Ride Book into her sword's slot.

Tri Cerberus!

Kenzan then charges the Fuusouken with electricity before delivers an electric slash that generates the Tri Cerberus God Beast. The God Beast charged at Desast before giving him an electric slash.

Desast decided to manipulate his red scarf and splinter it into multiple scarves for offensive purposes. The scarves aimed at Kenzan trying to hit or tie her up. Kenzan jumped onto a scarf as she changed Fuusouken back to Nitouryu Mode and threw it to hit any of the scarves around her as she ran on top of the red scarf.

She landed in front of Desast and did a spin strike attack sending spark as both swords hit each other. She then does a backflip kick Desast jaw.

"Ich!" Asuka counted.

She did another backflip kick.

"Ni!"

And one more kick.

"San!"

Kenzan landed on her feet as Desast grabs hold of her by the feet and tried to stab her with Gurajji Dento but blocked it with Fuusouken. When that didn't work Desast gave her a powerful kick, kicking himself of her.

Kenzan stumbled before turning back to Desast. "With my training with Fuusouken Hayate, I didn't know there would be stronger appoints. But I guess there will always somebody to challenge you.

"Hehe, I do like to give it my all." Desast mused.

Kenzan changed Fuusouken into Shuriken Mode.

Ittouryu!

She takes out Sarutobi Ninjaden from the Hayate Shelf and inserts it into Fuusouken's slot.

Sarutobi Ninjaden!

Kenzan holds Fuusouken tightly as it started to clean while a green tornado surrounds her before she pressed the Hayate Trigger.

"Shippū Kenbu Kaiten!" Asuka announces.

She then throws the Fuusouken Hayate at the enemy. Fuusouken then multiplies into several green-energy shurikens to attack Desast.

Ninnin! Hayate Sokudoku Geki! Ninnin!

Desast was distracted by blocking shuriken projections before the large got close making him block it and having a hard time holding it back.

"Hey, monster!" Asuka calling out to him. Desast looks up to see her standing on the academy's walls. "This is what happens when you hurt my friends!"

Desast knocks the giant shuriken projections but not before Kenzan then performs a spinning downward slash to him making the former try to block the attack. She spun till he couldn't block anymore making Desast drop his sword and Kenzan finish him off with a spinning downward slash. Desast screamed as she sliced through him destroying him in a small explosion not noticing the purple energy flying away.

Kenzan took a deep breath before jumping into the air with her fist in the air. "Yosha! I can't believe I did that!" She was going to praise herself more but remembered her friends. "Oh, right! I have to check everyone else." She de-henshin and ran to check on her friends.

~/~

The purple energy flies to the Hebijo Academy for evil ninjas where it floated to headmaster Dōgen's office.

Dōgen opens the Alter Ride Books of Desast resurrecting him again.

"So, how were they?" Dōgen asked.

"Well, the human girls were weak but…" Desast paused for a second.

"But?" Dōgen raised a brow.

"One did carry a Seiken," Desast answered. "Fuusouken Hayate, if I'm correct."

"Kenzan…" Dōgen hummed. "All the other Seikens were lost, but for Fuusouken to still be here…" Dōgen looks back at Desast. "Well, I hoped you enjoyed your battle with her?"

"I like to say she got lucky, but she was trained to use the Seiken," Desast answered. "But she gave me the thrill of being a worthy opponent," Desast says as began laughing.

AN: I hope you guys liked it because I was going to do an OC for Kenzan but after learning the previous Kenzan was a woman, then I thought I should make Asuka into Kenzan, not a male OC. Also, don't expect other Saber Riders to be in here because I might just make this a World of Ninja Riders even if there is a few of them, we'll see.

In other news, Zero-One Others: Kamen Rider Vulcan & Valkyrie was announced and Yua is finally getting her Final Form, Kamen Rider Valkyrie Justice Serval, which is reused materials from other forms. I mean she deserves it, she's like the third Rider! I mean Jin was the first one to get a Final Form even with him being the 4th Zero-One Rider. I mean even Ark-Zero got a Final Form, Ark-One! But I'm excited and waiting for KR Zaia henshin because I got a story ready for him.