WMG / Ryuk

Ryuk saw Gelus and Rem mooning over Misa before he ever dropped the Death Note.

So, he investigated the Japanese police, found one with an attractive male child Misa's age, and gave him the Death Note. Ryuk figured that this boy would be able to hunt down Misa when she got her Note if he knew about the Death Note, forcing Rem to sacrifice herself. Things worked out better then he ever expected, to his unending amusement.

• One problem: Ryuk doesn't find out that Light's father is with the police until the reader does.
  • That's what he says. Ryuk is known to conceal things to amuse himself.

The events of the series were a massive Gambit Roulette by Ryuk for the purpose of obtaining additional Death Notes.

He starts the series with two, and he would have had four at the end if Shidoh hadn't shown up and taken one. He's just waiting to pick them all up after the events transpire.

• If that was his plan it didn't work. Sidoh ended up reclaiming his Note, and Rem's and Gelus's were both burned by Near.

Ryuk is the reincarnation of The Joker.

Just think about it; Ryuk and the Joker are both evil beings with a very twisted sense of humor, whose only motive for committing their wicked deeds is simply to kill boredom and have fun. They even look and act vaguely similar, as they both sport pale faces with huge evil grins, and they also tend to cackle maniacally at others' misfortune.

Sometime in his final years, the Joker somehow got his hands on a Death Note (which as other theories have suggested, is a way for humans to become Shinigami). Unsurprisingly, the Joker enjoyed using his new toy to inflict greater levels of chaos and terror upon the world. But soon after Batman inevitably captured him and destroyed the killer notebook, Gotham City finally had enough of the clown's antics and executed him.

But that wasn't really the end for the Joker's villainy. He eventually returned to Earth as a spirit of death, ready to wreak chaos and havoc again for his own amusement. Luckily for Ryuk, he finds and corrupts Light, a nice young man who loves justice (sorta reminding him of an old foe). Not to mention that Light's father reminds Ryuk of another old foe, making it even more deliciously ironic.

Ryuk didn't toss the notebook at random. He deliberately chucked it at a school.

Oh, he claims it was all just an accident, but he's a known liar. It's as Light explains in the manga when he and L are building a profile for Kira — a teenager would be the most likely to use the notebook the way Kira did, anyone younger would be too scared to use it, and anyone older would just use it on occasion to kill people they didn't like. Ryuk knew this; he isn't very bright, but he is immortal.

Who knows how many times Ryuk has done this before? He might even know exactly what type of human would make the most amusing toy —someone who has never known hardship, so psychologically can't cope with having killed someone other than to SNAP in an amusing way... Ryuk might have even specifically targeted Light despite what he says: "You think I chose you because you're so smart or something?" He knew Light was "so smart" before even meeting him.

Ryuk made sure Gelus' Death Note fell into Misa's hands.

Ryuk introduced Gelus to Misa, and Rem to Gelus, so Misa would meet whoever gets the Notebook first. Oh, and Ryuk drops the Death Note near Light on purpose.

Ryuk is the first Shinigami psychopath, and Kira was just a side-effect of a sadistic game he was playing.

Shinigami generally operate on Blue-and-Orange Morality, but there is very clearly something wrong with Ryuk compared to the others. Ordinary Shinigami display few emotions, just apathy (some of them give so few fucks they nearly die from not writing enough names) or compassion (Rem and Gelus). Ryuk, on the other hand, appears to find human death and suffering hilarious, and is noted as being considered a weirdo by Shinigami because he diligently wrote down a lot of names in his notebook all the time. The other Shinigami killed intermittently because it's their job and life source; Ryuk killed lots of people because he enjoys it.

However, just writing down human names apparently got boring for Ryuk after a while, and he turned his mind towards something else; murdering his own kind. Ryuk mentions offhandedly that he wrote down the names of all his "friends" in the Shinigami world a number of times, but they didn't die, so he was actively attempting to kill the others before Light met him, he just didn't know how, being unaware of how Gelus bit it. Once it became clear his usual M.O. wasn't going to work on Shinigami, Ryuk decided to play a more subtle game by stealing some dumb chump's (Sidoh's) notebook, and electing to play "keep-away" with it until Sidoh ran out of lifespan and died, using the general apathy of his fellow Shinigami to steal their notebooks and starve them to death since he couldn't kill them outright.

To this end, he hurled Sidoh's notebook into the human world to get it as far away from him as possible, and planned to amuse himself by racking up as big a body count among the puny humans that picked it up as possible, until Sidoh ran out of time and he scored his first Shinigami kill. Things didn't go as planned for Ryuk, and Sidoh's alive and well, but Ryuk doesn't mind; his diversion amused him for a while, and there is nothing to stop him from trying again later.

Actually, Ryuk wanting to kill other Shinigami...did work because he found another way. Sure, he didn't kill dumbass Sidoh, but he did (through Light) kill much smarter, higher ranking Rem. Ryuk didn't know how to kill ANY Shinigami other than them running out of life via not writing names down until Misa told Light, and Rem told Misa. Before this, Rem was the ONLY one who knew of two ways to kill a Shinigami. Ryuk only knew they died if they ran out of life. Rem knew of another way. Because Ryuk never really helped Light at all, this ended with Rem falling in love with Misa, and then dying for her. So Ryuk succeeded at killing a Shinigami who was much more than Sidoh ever was. Rem fell into her own trap by sharing information on the OTHER way to kill Shinigami, which sadly led to Ryuk indirectly scoring his first Shinigami kill with Rem.

Everything in the series happened because Ryuk wrote it in his Death Note.

Ryuk, out of boredom, wrote down the events of the series in his Death Note, dropped his other Death Note in the human world, and kicked back to watch the show. As time went on, he continued to write things in his Death Note, finally ending with Light's death. It would certainly help to explain why, as a kind-of important character, he's never actually seen doing anything- as the "director" of sorts to the chain of events, he wouldn't have to.

• But the Death Note can only control people for 23 days... unless he was writing something like "* random name* . Drowns. Before drowning, he happens to pass a young man who is secretly Kira on the street. Said man then begins to plan a massive memory gambit wherein..."
  • It's quite possible the 23 day rule does NOT apply to Shinigami, since they're apparently the ones who made that rule (or their king is). Either way, it is quite believable that a Shinigami can easily bypass some of the less important rules, like that one. Heck, Ryuk might even have been able to completely ignore ALL the rules in the note, since they were written for humans, not Shinigami. He COULD have brought someone who was killed back to life, but why? It's more fun this way.
    • OR...ALL the rules in the notebook are fake in some way (ie. writing the name WILL kill someone, but erasing it could bring them back, Ryuk simply didn't care enough to mention the Death Eraser), but no one (at least no one human) has ever figured it out.

Ryuk was punished by the Shinigami King by having his eyes taken away.

Now I'm not saying Ryuk is blind... he seems to be able to see just fine in the relight films...what I mean is he had his Shinigami eyes taken away..which is why his eyes no longer have the red ring in them, but since Ryuk most likely got the lifespans of all the people Light killed over the course of death note... it will be a while before Ryuk has to worry about it.

• Great, now Ryuk HAS to go to the human world to find out peoples' names. I wonder if no longer being able to see names by looking at humans would allow Ryuk to enter the human world without possessing a person/letting them hold one of his Death Notes (we know he probably stole Sidoh's again)?

Ryuk will be the Last of His Kind one day.

Of the Shinigami, he's by far the most proactive one and tries to alleviate boredom. The Shinigami Realm is already rotting and there aren't many shinigami left. While some works hint that the Shinigami were Death Note users, going solely by the manga it suggests that a simple Cessation of Existence waits all humans(Death Note or not). It's possible that shinigami were created and have a fixed population, being unable to increase their numbers. The Shinigami Realm is a wasteland because it's incapable of renewing itself. With other shinigami known to die from forgetting to write names down or sacrificing themselves to save human lives, a day may come where all shinigami except the Shinigami King(who isn't the same type of shinigami but something else at least) and the proactive Ryuk die from a mix of boredom and laziness. Light has written more names in the Death Note than anyone, so that alone would give Ryuk a much larger lifespan than the other shinigami even if he does nothing from then on. Given what Ryuk's amusement led to with a number of other shinigami still alive, one can only imagine what he'd do with only the King to notice his actions.