からくり卍ばーすと (Karakuri卍Burst)

"からくり卍ばーすと " (Karakuri卍Burst), this is a duet sung by Kagamine Rin and Len, specifically their Append power voicebanks; becoming the append's first notable hit. It was composed by Hitoshizuku-P and illustrated by Suzunosuke. It's achieved over 400,000 views and is one of Hitoshizuku-P's many hits.
 * NND Broadcast
 * YouTube Broadcast

Background
Rin is shown standing beneath the moon, as if to approach. Len is shown standing before hundreds of dead bodies. Rin begins the song by singing about how she's visiting a sleepless town. Then, Rin pulls out a gun, and remarks that her fingers, once she pulls the trigger, also become stained in a brilliant red. Next, Rin sings about her desire to destroy. She says that humans are "worthless, brittle, and fragile", and that "they are, after all, merely discarded puppets". Finally, Rin asks why she was born, and for Len to tell her the answer.

Then, Len enters the song and sings about how there are no such things as coincidences. Len sings about his own desire to destroy. Len says that he'll destroy everything, and that he wants all sin to "die, die, die!!" He says that "all sinners are, after all, worthless pieces of scum". Then, Len asks Rin why she was born, and that he'll tell her the answer.

Suzunosuke has also made a doujinshi of the story and it is available in Toranoana (it was sold along side Hitoshizuku-P's album of the same title). The first part was available on Comiket, and the second part is soon to be released somewhere around Spring 2012.

The album contains three songs, and more information can be seen on the album page here.