If you don't watch Death Note, before starting, read this so I can explain a few things :))

Basically, Light Yagami is a man who is known by the world as "Kira" and Kira has the ability to kill anyone as long as he knows their real name and face. Any part of the world. And could even manipulate what they did before they died, and at what time they die. Light Yagami's father- was known as Chief Yagami. He was the Chief of police at the time. And Light was a genius, so he helped with the Kira case- of course they didn't know Light was Kira. Light had the right idea but lost himself completely.

L- L was the main detective in the show. And was just as smart as Light. He never showed his real name or face. And whenever he appeared, was on a computer screen, with a "L" on it. L was the first person to actually think Light Yagami was Kira and pulled multiple stunts to prove it when he and the task force met up, while they were saying L was disrespectful to even doubt the Chief's own son. When L is beginning to suspect Misa as the second Kira, and talks about her being executed, he is killed by Rem.

Misa Amane- Misa Amane was the second Kira. When she first appeared, she appeared as "The imposter Kira" by Light, as he knew she wasn't truly Kira. When the world found out there was two Kira's. Her name become "The Second Kira." Misa Amane is completely and utterly in love with Light Yagami and Kira, as Kira killed her parent's killer.

Watari- Watari was also a detective who stood by L's side. He was the only one who knew L's real name and face. But was killed by Rem when talking about executing Misa Amane with L.

|| I don't feel like explaining Matsuda, Ide, Aizawa. Basically, they are just cops on the task force, that were trying to catch Kira. The task force only contained around five cops, as the rest of the task force didnt dare defy Kira, as he started to kill anyone who stood in his way. ||

Kira- Kira is obsessed with being a god. He is a serial killer who's killed more than 900 criminals. He watches the news every day and criminals whose name and face were released to the public would be killed. Most died of a heart attack. Kira does not love or care about Misa/Second Kira. Kira does not have the Shinigami eyes. As he does not want to give up half his remaining lifespan, so he uses the second Kira, for her eyes.

Second Kira- The Second Kira is like Kira, but she's in love with him. She wants to achieve his goal no matter what it takes. In the episode where they meet, she asks to be his girlfriend and he says yes- he does not love or care about her, but she has extra power, so he uses her- acting like he loves her, when he is just using her. The second Kira has the Shinigami eyes.

Shinigami's- Shinigami's are gods of death that are the ones in possession of death notes. They are not able to be killed and it was confirmed in an episode, the only way to kill them is if they kill a human in order to protect another human. The only way to see a Shinigami is if you touch the death note they have. There is multiple Shinigami's in the Shinigami realm.
There is a deal you could make with the Shinigami whose death note you hold. Shinigami's have what we call "Shinigami Eyes" Shinigami Eyes allow you to see a person's real name and lifespan just by looking at their face.
The deal is that if you give the Shinigami half your remaining lifespan, they'll give you the Shinigami eyes.

Death Note- the death note is a book that allows the holder to kill anyone as long as you know their real name and face. There are multiple death notes in the Shinigami realm. Every Shinigami owns a death note, and very rarely do Shinigami's get more than one death note. Rem got another one by witnessing a Shinigami die and took their death note. And Ryuk stole another Shinigami's death note.

Ryuk- Ryuk is Kira's Shinigami. A Shinigami is a god of death. And all Shinigami's have a death note of their own. Very rarely do Shinigami's have two death notes- which explains why they rarely have death notes in the human world. It is said in multiple episodes that Ryuk does not care about Kira. And eventually kills him.

Rem- Rem is the second Kira's Shinigami. She cares deeply for the second Kira and would do anything for her, even if it meant dying for her. In an episode, Rem tells Light, that if he even thinks about killing Misa, Rem will not hesitate to write Lights name down and kill him. During an episode, the detective L starts to catch onto Misa, and talks about executing her, since Rem loves and cares for Misa so much, Rem kills L, protecting Misa, and killing herself. The Shinigami Rem, dies and Light Yagami finds her remains, and takes her death note.

There are deaths and stuff:')

Light Yagami- Shot by Matsuda but had a heart attack due to his name being written down by Ryuk.

Misa Amane- Killed Herself after Lights death

L- Heart Attack caused by Rem

Watari- Heart attack caused by Rem

Chief Yagami- Died in an explosion

So yeah<3