It was a tradition.
Every reincarnation he was going to fall in love with the same woman his master would and when her feelings for the master were the same, he would disappear, slowly into the darkness. His master wouldn't hear his voice anymore and with time he would forget it until the first man of the next generation reached the age of 14 and the love-gene would activate.
He felt lucky, because for a long time he was able to play with all those women, confuse their feelings and made them doubt their love for all those men who had been his masters. He always knew that, deep in their hearts, the women loved the men and that he was only a distraction that was born to disturb the souls of the unfortunate Niwa men, that he could never be with any of them and that's why he locked himself in his thoughts, because in the end he was nothing but an endless spirit, forced to reborn every time a Niwa was born.
But this time it was different. The moment he knew Harada Riku he felt something special about her. She was the one, the Sacred Maiden to his master and he made himself fall in love with her, because it was a matter of time until his master realized that they were meant to be and the cycle would be complete, as it always would. He knew Niwa Daisuke's feeling for Harada Risa were nothing but a crush and he didn't blame him, the girl was very pretty and knew how to show her charm. Yes, she looked exactly the same as Riku, her older sister, but they were completely different at the same time. Risa knew how to charm a boy and Daisuke couldn't escape from her, as every boy in their class, but she wasn't for him, he was destined to spend the rest of his life with Riku and Dark knew it.
At the beginning he acted crazy for the girl, he was going to do that until Daisuke noticed her and her feelings, feelings he broke every time he tried to make a move with her sister. It wasn't until Saint White's Day that something happened inside Daisuke and he started to realize that Riku was something more than just a good friend. His heart started racing with that almost kiss and Risa was just an illusion in his head. He knew the moment was coming. Soon they were going to fall in love and Riku would knew about the curse, about him and she would understand and choose the young Niwa, then he would disappear until their first baby boy was born. Just like every reincarnation.
But what about Risa? He asked to himself.
Every since she saw him on tv, she started following him. She claimed he was perfect for her, that he was the boy she needed to finally defeat her sister at something. She fell in love at first sight.
Of course, Risa wasn't the only one who fell in love with him at first sight, almost every other girl on the Azumano district did. How wouldn't they? Wasn't a bad boy the dream of every teenager in the world? Dark was the perfect example of a bad boy. Sexy, smooth, a white glove thief who was able to steal the most protected artwork in the world and the hearts of all the girls around. It was ridiculous to think Risa, being as shallow as she was, wouldn't like him. He was her ideal of the perfect boyfriend.
For a long time she followed every step the thief did. She was always trying to be in the scene of the crime, looking as pretty as she could, so he could notice her between the multitudes. Little she knew that the thief always noticed her, mostly because she looked exactly the same as his "real love".
More than once he played around with her, like he used to do with every beautiful woman. He would seduce her, called her lovely names and talk soft to her and she would feel special. She would hug him, call his name and beg for him to return her feelings, but he would think about Riku and the curse, her older sister was his destiny and he couldn't look another way. But there was something about her voice that would always echo in his head and made him feel kind of weird. That's why more than once he kissed her or tried to, like that time he found her sleeping on her bed, recovering from a hard cold. She looked so innocent; he wondered if she was dreaming about him. Then an idea hit him: he was a thief, maybe was able to steal a cold too. He brought his lips close to hers; he could feel her breath and the sweet smell of her rose tinted perfume or maybe it was just her natural essence, he didn't know. He was about to kiss her when Riku appeared and destroyed the moment. Riku with her strong personality, Riku with her bad attitude towards him. The one who was destined to continue the Niwa line. Just Riku.
It was the day Freedert and Elliot reunited again when he realized he could never really love the older Harada. When he saw those two existences that waited for each other, who never stopped thinking about the other and accepted the other with all its failures embracing for one last time, he knew he couldn't love the same person his master did.
It was new. For years, maybe centuries, he wasn't sure, he always "fell in love" with the same woman his master did. Their hearts would beat at the same time and the transformations would be under control, because the love-gene was reacting the same way for both. It was the first time he fell out of love with the girl. Maybe, he thought, he never fell in love with her, but he just knew the first time he saw her that she was the one for his master and accepted the idea of falling in love with her, because that was how it always worked.
He felt lost, but he couldn't do anything about it, because in the end he was going to disappear, just like he always did. But then it happened. They bumped into each other, it was an accident or maybe it was destiny, he didn't know. All he knew was he was happy to see her. He hugged her, he told her he was busy and that's why he didn't show in front of her for a while, he wasn't lying, he just couldn't lie to her. When her lips were touching his and her arms were around him a stroke of pleasure hit him in the chest. His body felt warm and relaxed for the first time. She said some words about running away, that he was in a dangerous position and then tried to stop some girls in the hallway. He just stayed there, in the floor, still thinking about the kiss, not noticing he turned into his master. This couldn't be happening.
It was like a big joke. He was an existence, a soul without a body condemned to vague between the lives of the Niwa clan, he couldn't think about other woman that way. Damn! He couldn't feel for any other woman but the one his master chose. But he was. He was thinking about her, he was having feelings for her; the one he thought was just his master's crush and looked the same as the Sacred Maiden. The girl who always waited for him and had faith that one day he could return her feelings. The one who's voice he couldn't help but hear in his heart.
He knew his feelings were doomed and wanted to explain it to her, so he asked her out on a date. Funny, but the date wasn't what he thought it would be. He thought he was going to tell her the truth of his nature the moment he had her in front of him, but he couldn't. He wasn't going to ruin her perfect day right away; he was going to wait a little longer. He just didn't know that she was going to react so well to the idea of being in love with a monster. "No matter where, no matter when, I will always be with you". Her words were like a sword in his heart. He knew he was in love for the first time, but it couldn't be.
They were on the Ferris wheel, looking at the park and enjoying what was supposed to be their last time together when he felt a disturbance in the energy. Everything went to black and he had to leave her to see what was going on. When he was back she wasn't there anymore, just her cell phone on the floor. He went crazy and almost got caught by the police, his ability to change back became weak and he was trapped inside the body of his master. He felt useless. But his master wasn't going to stop and kept looking for her, because in the end she was his friend and he knew Dark had feelings for her. He joined Hiwatari Satoshi, a classmate and his supposed nemesis, who always happened to be there when Risa was involved in something dangerous, and they found her; she was kidnapped by Argentine, a forgotten work of art.
And he was back in action. He fought against Argentine; he wasn't going to let him take what belonged to him. Screw the curse, Risa was the woman he loved and no one was going to keep them apart. Not even his master or this Argentine. But what about a third one? Satoshi was always there and he was able to rescue her when he couldn't. He saw them from the distance. He, on his angel form, was holding her in his arms and taking her to somewhere safe. He saw her saying something to him, trying to make him stay and asking why he saved her. He was asking himself the same question. Why did he save her? Is she his Maiden? No, she can't be. She belongs with him and no one else.
Then she sees him, she hugs him and thanks him for going to her rescue. He wants to stay there forever, even if she's really hugging his master trying to look like him, not his real self. He's happy to see her save and since the moment she back at home he decides it would be better if every night, after she goes to sleep, he goes and check her, just to see everything is alright. He does it every day until she's trapped in the mirror's world. He asks himself how does she manages to get herself in troubles all the time, but he knows it isn't her fault, she just has a something that attracts the Hikari works, the ones that belongs to Satoshi's family, who once again is there trying to rescue her. He just doesn't like that boy.
When Risa's back there's something different in her. She acts different with Daisuke and asks him to go to the school's dance with her sister and her, but when he dances with her, he must act like Dark. He has the feeling she knows the secret.
Daisuke, who managed to dress not like a dork for the first time, dances with Risa. He tries hard to be the perfect faux-Dark for her and for him, who wanted to go to the dance just to share a piece with his lady, but he fails. There's no chemistry. There's love, of course there's love, he learnt to love her like a sister, but there's no spark and you can feel it when they dance. Dark can see Satoshi looking at her for a corner of Daisuke's eye and then disappear with an older man. That's when Risa talks and explain to Daisuke how much she wanted to share a dance with Dark, but she knew how impossible it was and that why she asked him to act like the thief. He doesn't know how it happened, but he felt her hand on his, not Daisuke's. He started to look at her with his own eyes and the temperature of Daisuke's body (or was it his?) started to rise.
He started to run, Daisuke started to run. They bumped into Riku, but they didn't care, they just wanted to disappear. They found a little gallery surrounded by plants and stayed there, trying to calm down. But they can't, Risa followed them. She runs and hugs him, she knew he was going to be there and they realize Daisuke somehow managed to turn into Dark. He hugs her, he says he will always be there if she needs him and they dance. It isn't awkward, it isn't weird, it's just a perfect little moment between two people who love each other and can't seem to enjoy somebody else's company.
It's when they stop dancing when Risa asks the question he always feared. "How is it Niwa-kun and you always dress the same way and are in the same place at the same time?" She knows, he knows that she knows. He tries to explain, but he can't seem to find the words. That's when Daisuke starts speaking through him. He tells her about the curse and Dark's existence, she listens and nods. After a few minutes of silence she did what she does best: she hugged him.
He was in shock for a while. He thought that when the day comes she would have feel offended and would have leave him on his own, but she was hugging him as if nothing else mattered.
"How much time you have left?" She asked, not letting go of the hug. "It depends on your sister". He could feel the tears coming down from her face to his shirt and felt guilty; he didn't want her to cry. "Then it's not too much". Risa cleaned up a tear from her cheek and then looked into his eyes. Her big brown eyes were shinning thanks to the water in them, but were as pretty as they always were. He knew she wanted to say something, but was afraid of her words. Would she hurt his feelings? Would she say it's over, because Daisuke belongs with Riku and she doesn't want to get in the middle of her sister's happiness? Would she leave him alone?
"I will always choose you" She said. "It doesn't matter if you're gone, I'm old and my hair became gray. I will always choose you" He didn't know what to say. Was she being serious? She couldn't be. "I know it sounds stupid, but it's true. It doesn't matter if I end up marrying someone else and having kids, that person will never be as important to me as you were, are and will always be".
For centuries, Dark Mousy the Phantom Thief has stole the most beautiful works of art of the world. His white glove tactics are well known around the globe and it's every policeman dream to get his hands over him, to be the one who finally captured the man who moves like a shadow. He never imagined it'd be a girl like Risa the one who finally capture him. But he was glad it was her, because no one else could ever read him like she did. She's the only one who really cared for him and opened up her heart, even knowing he was an eternal existence condemned to reborn every Niwa generation.
Dark searched himself trying to hear Daisuke's voice, but he's silent. He knows the boy isn't comfortable with the situation, but he respects the moment and wants his alter ego to enjoy himself for the first time. He's glad about it and let a little smile appear in his face. Suddenly he senses a presence he knows very well. Somewhere near the dance Krad is taking over Satoshi's body. He knows the final battle, the one that will decide his destiny is getting closer. Risa notices something different in him and the expression of his face helps her to understand what's going on.
She kisses him one last time before the imminent war begins, he holds her closer than ever. Daisuke's voice starts to echo inside him and he knows it's time.
A dark figure flies through the sky at the same time the Azumano High School's dance comes to an end, while a brown haired girl holds into a black feather, looking up at the sky, praying that this won't be the last time she sees the thief who stole her heart.