Eyeballs

 Eyeballs (眼球 Gankyū) is the fifth chapter in the Death Note manga. The events in this chapter take place in episode 3 of the anime, Dealings (取引 Torihiki).

Plot
At L's request, the American FBI has sent a number of agents to Japan in order to find out who is leaking information to Kira. L is convinced that the mass murderer is either a member of the Kira Task Force or a friend or family member. Among those who will be investigated are the leader of the Task Force, Soichiro Yagami, his wife Sachiko and their children, Sayu and Light!

Light has been attending after-school classes as part of studying for the entrance exams for university. He is followed everywhere by Ryuk who cannot be seen by anyone else. One evening, as they are making their way home, Ryuk tells Light that he has to talk to him on an important matter.

Ryuk begins by making one think clear: He is not on Light's side nor L's! He will not judge if what Light is doing is right or wrong, he'll just let him use the Death Note as he sees fit and observe the battle of wills between him and L &mdash; which he is enjoying no end. However, something has come up which bothers him on a personal level: They are being followed!

A man has been following Light from a distance for the past couple of days. He cannot see Ryuk but the Shinigami still feels uncomfortable about this. Light tells him that he will deal with the matter.

Light returns home and goes to his room. He now leaves small pieces of paper at the bottom of the door which come loose if anyone tries to enter it without him knowing. The paper is still there.

It has been a week since the leak was discovered and Light believes that he is not the only one being investigated. The Task Force includes almost a hundred people so there are plenty of suspects to check up on, but if the investigators then probe too deeply then Light may eventually get found out!

The first thing to do would be to obtain the name of the man who is following him. The question is how?

Light is pondering this when Ryuk tells him that there are two major differences between a Shinigami and a human who uses a Death Note. The first difference is that Shinigami use Death Notes to kill humans in order to live longer!

If, for example, a man was supposed to live till he was sixty and was killed by a Shinigami when he was forty then his remaining twenty years would pass on to that Shinigami. Shinigami cannot be killed by conventional ways such as guns or knives but they can die if they fail to kill humans in order to increase their lifespans. Ryuk does know that there is an actual way to kill a Shinigami but does not know how it is done.

Shinigami do not really care for humans and whether killing them will make the world a better place or not. In fact, life for most of the Shinigami has become so meaningless that most of them just laze about in the Shinigami Realm, simply killing in order to live longer with no real goal in life. Light suggests that when he returns to the Shinigami Realm, Ryuk take with him some of the things that he has learned on Earth and liven the place up a bit.

Humans who use the Death Note do not get extra years on their lives when they kill other humans. That is the first main difference between humans and Shinigami.

Another difference is to do with their eyes! In order to kill a human, Shinigami simply have to look at one and they will be able to see that person's name and lifespan! By looking at his present companion, Ryuk can see his name, "Light Yagami", and a set of numbers, "93312639". These numbers can be converted into human time and thus Ryuk will be able to know how long Light has to live.

Ryuk will not tell Light how long he has to live for, neither will he tell him the name of the man who has been following them. However, there is a way round that: A deal by which a human could acquire the Shinigami Eyes!

Ryuk explains that a human who owns a Death Note can make a deal with the Shinigami who originally possessed it. If Light agrees to the deal then he will acquire the power of the Shinigami Eyes and be able to see the names of other humans, including that of the man who is following him!

However, the Shinigami Eyes comes with a price: In order to get them Light must give Ryuk half his remaining lifespan!

Plot Points
Ryuk says that there is a way to kill a Shinigami but does not know exactly how it is done. This is demonstrated in chapter 27 "Love".

Conception
The chapter's title "Eyeballs" relates to the Shinigami Eye deal that Light could make with Ryuk. Ohba believed that titles like "Eyes" or "Trade" were not interesting enough and decided that "Eyeballs" "sounded cooler."