Red and black, however black is tech. a shade. Why? Because the many hues of red stir thoughts of warmth, anger, and blood. (Mind you I'm not suggesting anything) Black because it can be used to dampen any color and symbolizes the unknown, the dark, and all the creepy crawlies that scare us that we can't see. *yawns* I think too much...

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Should the owner of a Death Note be killed, the killer now becomes owner of their Death Note...