Heartbeat Clocktower

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"Heartbeat Clocktower" was not the first of these songs to be released; it was released April 25, 2010, long after many of the songs had been released. However, it serves as an overarching theme for all of the songs, as well as establishing a background. It is the fourth song in the "Clockwork Lullaby" series.

The song concerns a mysterious clocktower and its actual guardian, GEAR. The dead owner and former guardian of the clocktower, the "Collector" (Gallerian Marlon), created a "Theater" for the "Collectibles" - they forever enact their story, while hapless visitors end up prey to the "Master of the Graveyard". The "collectibles" are presumably the representatives of the seven sins. There are four main parts to the clocktower, the "heavenly yard," the "hellish yard," the "graveyard," and "the court." GEAR's main concern is to keep a young girl "with ugly burns on her body" (Clockwork Doll) alive through the clocktower, and if it stops, she will die. He also describes other inhabitants of the clocktower, including a "pretentious" servant girl (Waiter) who "indulges in selfishness", but expresses sadness for the loss of her "other half" (Irregular). He also mentions "blood-stained scissors" (Kayo's Scissors) and "a purple sword" (Venom Sword), neither of whom have "awakened" yet. The former guardian of the clocktower, which keeps the theater running, had been the embodiment of greed; the current guardian, realizing that the clock was going to stop soon, sacrificed himself to keep it running by taking out his own heart and using it to power the clocktower. The official English title of the song is "Clockwork Lullaby 4".

Singing Roles
KAITO as GEAR

Non-Singing Roles
Miku Hatsune as Clockwork Doll

MEIKO as Master of the Graveyard

Rin Kagamine as Waiter