It has been fifteen years now since Saya fell asleep after killing Diva. Her two nieces are now enrolled in her old school, and Kai has taken over their dad's restaurant, which is where this story begins.
"It's been a while Kai," said David as he walked in the front door.
"Hey David, so you here to check up on me?" asked Kai who has not changed at all in the past fifteen years.
"Just wanted to make sure you and the twins were doing ok," said David as he sat at a table.
"Kanade and Hibiki are fine, they even have a few friends at school," said Kai as he washed some dishes.
"And how are you, I know it must be tough being a chiropteran now," said David.
"I'm doing fine, but I know you're hiding something," said Kai as he stopped washing the dishes.
"He is as smart as you told me," said a teenage boy with brown hair and reddish brown eyes as he walked in.
"And who are you?" asked Kai with a suspicious look on his face.
"The name's Rin, and I'm here to wake Saya," said the boy.
"What," said Kai with a worried yet surprised expression.
"I'll explain," said Rin as he took a seat next to David. A few hours later at the Miyagusuku family crypt.
"So, how exactly are you going to wake Saya up?" asked Kai as he stood in front of the door with a bag of cloths in his right hand.
"Just open the door and get the stuff ready," said Rin. Kai then opened the door and Rin started a haunting whistle that grew louder and louder. Suddenly, a noise that sounded like something hitting the ground came from the crypt once he stopped the whistling.
"There she's awake," said Rin.
"Saya," said Kai from outside the crypt.
"Kai is that you?" asked Saya from inside the crypt.
"You really are awake," said Kai as he moved toward the door.
"Don't you even think of coming in her!" said Saya in a loud voice.
"Toss her the bag," said Rin as he slapped Kai on the shoulder.
"Here Saya," said Kai as he put an arm into the doorway and tossed the bag into the crypt.
"A few minutes later Saya walked out wearing a black shirt, a pair of jeans, a purple leather jacket, and black leather boots.
"Nice to see that you kept the jacket and boots," said Saya who's hair was super long.
"Looks like you need another haircut," said Kai as he moved her hair out of her face.
"So who are you?" asked Saya as she looked at Rin.
"My name's Rin, I'm your cousin," said Rin as he held out his right hand.
"Wait, I thought chiropterans could only have daughters," said Saya with a surprised face.
"The first queen to have children has twin girls like your mom," said Rin as he withdrew his hand.
"So you're my younger cousin," said Saya.
"Yes, my mom got pregnant two months after yours," said Rin.
"Do you have a twin?" asked Saya.
"Yes, and she's the reason I'm here," said Rin with a sad expression.
"What do you mean?" asked Saya.
"My fraternal twin sister Shairn is trying to destroy both the human and chiropteran races, and I need your help Saya," said Rin.
"So the reason you woke her up early was to get her to help you," said Kai with an angry tone of voice.
"Whoa, wait a minute, how long exactly have I been asleep?" asked Saya who had no clue about how long it has been.
"Fifteen years," said Kai.
"Only fifteen years!" said a surprised Saya.
"And he's the one who woke you up," said Kai as he looked at Rin with angry eyes.
"And I didn't just do it for me, I'm here to help you two as well," said Rin.
"How's that?" asked Kai who was still a bit suspicious of him.
"My blood can make it so you're not immortal any more, but still have other powers," said Rin.
"Your blood doesn't turn chiropteran to stone?" asked Saya.
"No, to monster ones it makes them fully human again, they won't remember anything they did, and are healthier than ever before," said Rin.
"And what about chevaliers?" asked Kai.
"It takes your immortality away, same with full chiropterans like Saya," said Rin.
"Then why not use your blood on your sister?" asked Saya.
"It has no effect since her blood has the same effect," said Rin as he took a seat on the top step.
"Can you guys have chevaliers?" asked Saya as she sat next to him.
"Yes, but mine's not with me right now," said Rin.
"So you want Saya's help since your blood can't kill your sister?" asked Kai as he and Saya sat next to him.
"Exactly, so what do you say, do you want to join me in my fight," said Rin as he looked at Saya.
"Only if you tell us what you're not telling us," said Saya.
"My blood can also make chevaliers able to have kids with their queens, is that something you two would like to be part of?" said Rin
"You have a deal," said Saya with a blushed face