Grand Unifying Guesses/Death Note

Possible Kiras:

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 * Kira: || Shinigami || Eye Deal? ||
 * Calvin || Hobbes || No ||
 * Megan Parker (future) || Unknown || 50/50 chance ||
 * Dr. Bob Kelso || Enid || No ||
 * Stewie Griffin || Ryuk, Brian, or Rupert || Only in Relevant Cutaways ||
 * Jessica Fletcher || her editor || Yes ||
 * Maximum the Hormone || Ryuk, Rem, and any others || Maybe ||
 * Edgar Allen Poe and Bobby the Stalker || the Raven || Yes ||
 * Nathan Petrelli || Linderman || No ||
 * Sylar || his mother || Yes ||
 * Matt Parkman || Sylar || No ||
 * Jeremy Greer || Unknown || Yes ||
 * Gaius Baltar || Chip-Six || No ||
 * Donnie Darko || Frank || Maybe? ||
 * John Crichton || "Harvey" || No ||
 * Lelouch Lamperouge || C.C. || Yes ||
 * Aeolia Schenberg || Unknown || No ||
 * Setsuna F. Seiei || Gundam! || No ||
 * Sweeney Todd || "a dark and a hungry god" || Maybe ||
 * Owen Harper || Janet (the Weevil) || No ||
 * Tyler Carson || Unknown || Yes ||
 * Santa Claus || his reindeer || Yes ||
 * Spongebob Squarepants || The Flying Dutchman || No ||
 * Zac Efron || The collective will of the masses || No ||
 * Joe Quesada || An Anthropomorphic Manifestation of Inflated Ego || Yes ||
 * Ichigo Kurosaki || Rukia Kuchiki || Yes ||
 * Orihime Inoue || her faeries || No ||
 * Doctor Faustus || Mephistophiles || Yes ||
 * Doctor Horrible || Moist? || No ||
 * Millie || Locke || No ||
 * Bruce Wayne (Nice hoodie and transistor radio set there in Begins though he apparently gave up ownership before killing anybody.) || Obviously something with a bat-motif, possibly Rem? || No ||
 * Ra's Al Ghul ("FOR TRUE JUSTICE!") || Unknown || No ||
 * Harvey Dent ("You either die a hero or live long enough to see yourself become the villain.") || Unknown || Possibly. ||
 * The Joker ("It's all part of the plan.") || Ryuk || Who knows? ||
 * Every troper || TV Tropes || No ||
 * Alton Brown || The Chairman || No - he hates unitaskers. ||
 * Dexter Morgan || The Dark Passenger || No ||
 * Clyde Shelton || Unknown || No ||
 * The narrator of Fight Club || Tyler Durden || Unknown ||
 * Ma-Ti (What kind of lame power is heart, huh? Whos Laughing Now) || a big blue guy with green hair || No ||
 * One or more Magical Girls || Kyubey || Maybe ||

But in Zetsubou Billy, the lead singer of Maximum the Hormone stated that he and his band are Kiras, and so are we ("Even you're Kira!"), so what does that mean?
 * It means that they were lying.

The implications of this are disturbing...
Teen Girl Squad is what happens when somebody draws a comic in a Death Note - that girl who wrote the email SPECIFICALLY TOLD STRONG BAD ALL HER FRIENDS' NAMES. You notice she never wrote back to him.
 * Doesn't this make Strong Bad a Kira then?
 * Note: Only Kristen's name was written in the comic. Therefore, she is probably dead. The rest of them are fine. Also note that Strong Bad did not use his real name. At least, I don't think so...* eerie music?*
 * But you have to know what someone looks like to use a Death Note.

Death Note takes place in the same universe as Dead Like Me
There is a person mentally contected to each book who receives the names of people about to die. They in turn pass the names onto the leader of a reaper group, and this is how they know who is going to die.

Death Note takes place in the same universe as Mirrormask
There is a reason that everyone in that world wears a mask, are afraid to show their faces, and say as little of their name as they possibly can. Also, see the fanfiction "The Faceless" which has people wearing masks 24/7.

Lorien is the Shinigami King.
Lorien is an immortal being that knows and can tell humans their remaining lifespan. It makes sense that he's the Shinigami King since the King makes the rules and if he so wishes can circumvent the rules of death.