Most Vocaloid sad story ever - Aku No series

Aku No series is most popular series of Vocaloid song, and sung by both Kagamine Rin and Len. There are 4 song of this series, which each of PV is a plot of this series.

AKU NO MUSUME/Daughter Of Evil
Sung by Rin. The story begin when young princess, Kagamine Rin rule in one kingdom. She is very cruel and selfish. She also have a loyal servant, Kagamine Len, which he is also her twins. She has fall love with Kaito which is prince from Blue Country. However, Kaito has fall love to Hatsune Miku which is princess of Green Country. Angry about this, Rin order Len to kill Miku and ruins the Green Country. All people stand up and fight with Rin Soldier and success catch the young princess. Princess Rin dead at the end of video/song.

Aku no Meshitsukai/Servant Of Evil
Sung by Len. This is one of famous Len song. This PV tell that he is servant for Princess Rin, and he very love his twins. He follow all order from Rin, no matter what. He fall in love with Miku which the princess of Green Country, and he also murderer of Miku because he love his Rin more. In order to save Princess Rin in war, he tell Rin to switch the cloth and ask Rin to run. The story end when this fake princess dead, while real princess escape.

Regret Message
Song by Rin, the story continue when Rin very regret at what has happened. The scene is at the sea shower and she holding the bottle message and she regret about Len death and how selfish her is. She also pray that she hope she and Len will reborn and be twins again and release the bottle into sea. In the end of story, she has "reborn" and shocked when see Len front of her.

Re-Birthday
Sung by Len. After dead, he found out that he is dark place. He regret about what happened and about his sin. He's hands fastened by red handcuffs and his ankles in blue shackles. Sunddenly he hear a voice say "You will reborn", which is wish from Rin has been granted and you know what the ending right? :)