Well, here's is half of the background to why they are siblings. This goes into the detail. The next chapter takes up where this one left off, I promise you get the whole story. Anyway, this is one of the long chapters I promised you, so, well, here it is. :)

Chapter 17

"What?" Kyo cried finally when he found his voice. "Y-you mean Tohru's my, my sister?"

"Half-sister, actually," Kazuma corrected.

"I-I can't believe it," he sighed. "You're trying to tell me that Tohru, Tohru Honda, is my sister."

"She is officially Tohru Sohma," Hatori corrected.

"T-Tohru Sohma?" Tohru squeaked, speaking for the first time since they had received the news.

"That's right, Tohru," Hatori nodded.

"H-how is that possible?" she asked.

"Kazuma can tell you the story better than I can," Hatori said.

"Master?" Kyo asked, turning to stare into Kazuma's eyes as Tohru did the same.

"Kyo, I should have told you this a long time ago but I was afraid of what Akito would do, he was planning on using this information against you, but now it's time," Kazuma said apologetically.

19 Years Ago

"Kyoko Honda, will you marry me?" came the voice of a black haired man who was down on one knee holding onto the hand of a beautiful woman with sparkling red hair that glistened under the sunlight.

"Oh, Katsuya, of course I will," she breathed, falling into his arms as he began to kiss her.

"Oh, Kyoko, you're so beautiful," he murmured in her ear. Her arms were wrapped around his neck and his around her waist. She giggled with delight as she felt his lips on her neck.

"Katsuya," she repeated.

"What do you think your parents will say?" he asked abruptly, pulling her away from his body, a hint of fear in his eyes.

"I'm not exactly on speaking terms with my parents. Ever since Rubette slipped about me being the red butterfly they haven't even acknowledged my presence," Kyoko replied casually. "At this point I don't think they care what I do."

"What about Rubette?" Katsuya asked.

"She's still their little angel but I can't hold anything against her, she's my sister and the only one in my family who respects me," she replied.

"So I assume you want to elope," he suggested.

"Oh, Katsuya, it would be so romantic, we could-" she started.

"Hold your horses, I've already got it all planned out, I just wanted to make sure you were all right with eloping," Katsuya said as she squealed with pleasure.

"So, when are we getting married?" she asked.

"That depends on your schedule," he replied.

"Well, being married would automatically kick me out of the gang so I'll have to hand over my leadership to one of the gang, I'll have to run all those willing through the test, but that shouldn't take long. How about next week?" Kyoko asked.

"It sounds wonderful," he said, pulling her into his body and covering her lips with his as he wrapped his arms around her waist.

"So, how was the honeymoon?" a red-headed woman asked Katsuya.

"Absolutely wonderful, except for one thing," he said.

"What's that?" she asked.

"I missed you," he whispered gently as he slipped his arms around her slender waist.

"Katsuya," she said, squirming out of his arms.

"What is it, Rubette?" he asked.

"You're married now, I felt horrible from the beginning but I loved you much I didn't care. Kyoko's my sister, not only my sister but my identical twin sister. We have a special connection that no other siblings have. Now you're married to her and she loves you more than life itself, I couldn't hurt her," Rubette said.

"Oh, Rubette, I love her more than life itself too, but I love you exactly that same," he said.

"Oh, Katsuya, I love you too, but Kyoko-" she started.

"Kyoko doesn't have to find out," he whispered. At that moment her heart broke as she stared into his beautiful eyes. She wanted to refuse, to end their relationship there, but her love for him exceeded her love for Kyoko. She felt guilty even as she agreed and their lips touched, but the sensation of his warm lips against hers enchanted her as she melted into his arms.

"Rubette called today, Katsuya, said she wanted to speak with you," Kyoko said as Katsuya walked through the doorway of their new home. His eyes grew wide at the news.

"Was she okay?" he asked.

"Well, she did seem a bit upset, now that you mention it," Kyoko said.

"I'd better go over there and see her," he said.

"I'll come with you, Katsuya, you're starting to make me worry now," Kyoko decided as Katsuya's eyes widened with fear. He had a feeling that whatever Rubette wanted to tell him wasn't something she wanted Kyoko to hear.

"Pregnant!" Kyoko shouted, leaping from the chair in which she was seated. Rubette slowly nodded. "I told you that I was eloping, how could you go off and get married without telling me?"

"I'm not married, Kyoko," she said softly.

"Rubette, I never thought you were capable of doing something so dirty. Who's the father?" she asked. Rubette's eyes filled with tears and she broke down as Kyoko just stared. Katsuya sat on the couch across from her, looking extremely uncomfortable. Kyoko wasn't dumb, she could put pieces together in her mind, and as she slowly turned her head to look at Katsuya he wriggled uncomfortably, staring at the floor. "Katsuya, Rubette is it Katsuya?"

"I'm so sorry, Kyoko!" she cried with a nod. Kyoko's eyes immediately filled with tears. To Katsuya's surprise Kyoko wasn't angry but extremely hurt. A few tears fell down her cheek and she turned to look at the man.

"How could you?" she cried. "How could you do this to me?"

"Kyoko, I loved both of you from the very beginning, I couldn't help myself!" he shouted, tears now falling from his eyes.

"Oh, Katsuya, I loved you so much, so help me I still do, but you've hurt me more than I've ever been hurt before," she said bitterly.

"I know, I know, and if there was any way to repay you I would," he said.

"You'll never be able to repay me, but there is something you can do for me," Kyoko said.

"Anything," Rubette choked before Katsuya could reply. He nodded fiercely.

"Name your child after me," she said solemnly.

"Oh, yes, but what if it's a boy?" Rubette asked.

"Name him, name him Kyo," she declared. The two nodded as a period of silence fell over the room, only broken be Rubette's occasional sniffles. Finally Kyoko spoke again. "I guess now is as good a time as any to tell you my news."

"What news?" Katsuya asked, looking up into her eyes.

"I'm pregnant too," she said softly. Katsuya just stared at her as Rubette followed. They were both in shock.

"It's a boy," a beautiful young nurse announced to Rubette as she handed the squirming baby to her.

"Kyo," Rubette whispered gently, caressing the tiny body in her arms. Suddenly the boy's figure started to change and in a cloud of dust it disappeared. What was revealed was the ugliest creature she had ever seen, and with it came a stench as rancid as a rotting, dead body. She screamed and dropped it on the bed as Katsuya came running. The nurse was in a panic.

"What's wrong?" he asked, but as soon as he did he saw the creature on the bed and drew away. "That's my child?" Rubette nodded, tears streaming down her face.

Just then Katsuya remembered the Sohma curse and how his grandfather had been cursed with the spirit of the cat. He was the only child of his parents but his cousin, Kazuma, also shared the same grandfather. Kazuma was in the waiting room now, maybe he would know what to do. Katsuya ran out of the room, dragging Kazuma in as he returned. He pointed at the ugly figure lying on the bed as Rubette continued to cry. Kazuma reached into his pocket without a word and pulled out a black and white beaded bracelet. He touched the tiny claw and placed the bracelet around it. The figure immediately turned back into the human child Rubette had been given.

"What does this mean?" she asked with a trembling voice.

"Your son is cursed with the Zodiac curse of the cat," Kazuma replied. "The Sohmas have held this curse for generations. When they are embraced by a member of the opposite sex that is not cursed they immediately transform into their Zodiac animal. I'm sure you're familiar with the old story of the animals, Miss Rubette." She nodded. "As you know the cat is the animal left out of the Zodiac and as such it carries a heavier burden. Not only does it transform into a cat when embraced, but it also turns into the cursed spirit of the cat when it's not wearing this bracelet."

"S-so, you mean I can't even hold my child?" Rubette cried, tears in her eyes again. Kazuma, pain in his eyes, nodded slowly. Rubette burst into tears as Katsuya put his arms around her shivering shoulders, tears forming in his eyes. He cried for Rubette, but also Kyoko, hoping the same would not happen to her child.