Part I

Part I is the first part of the anime and manga. This part primarily focuses on a mind battle between Kira, who is 17-year old Light Yagami, and L, an eccentric detective seeking to catch Kira. This part of the anime is often referred to "season 1" by fans.

During interviews, Tsugumi Ohba and Takeshi Obata refer to this part as the "L arc". Many fans also use this name.

Characters
The following is a list of characters featured in this part. Characters who are mentioned are italicized.
 * Light Yagami
 * L
 * Misa Amane
 * Ryuk
 * Rem
 * Gelus
 * King of Death
 * Soichiro Yagami
 * Naomi Misora
 * Kiyomi Takada
 * Watari
 * Touta Matsuda
 * Sayu Yagami
 * Sachiko Yagami
 * Kyosuke Higuchi
 * Raye Penber
 * Shuichi Aizawa
 * Lind L. Tailor
 * Yuri
 * Calikarcha
 * Gook
 * Deridovely
 * Zellogi
 * Wedy
 * Aiber
 * Hirokazu Ukita
 * Hideki Ryuga
 * Reiji Namikawa
 * Hideki Ide
 * Hitoshi Demegawa
 * Misa Amane's stalker
 * Arayoshi Hatori
 * Kiichiro Osoreda
 * Yumi Aizawa
 * Takuo Shibuimaru
 * Shingo Mido
 * Kurou Otoharada
 * Emi
 * Eiichi Takahashi
 * Eriko Aizawa
 * Koreyoshi Kitamura
 * Yamamoto
 * Yoshio Anderson
 * Masahiko Kida
 * Masaaki Shirami
 * Takeshi Ooi
 * Suguru Shimura
 * Ryo
 * Shiho
 * Ginzo Kaneboshi
 * Kyoko
 * Yukito Shiraba
 * Sudou
 * Nori
 * English teacher
 * Film director
 * Tasayoshi Yoda
 * Yasunaga
 * Sasaki
 * Yonegoro Nusumi
 * Unnamed woman
 * Yoshi
 * Light Yagami's friend
 * Misa Amane's friend
 * Matsushiro Nakaokaji
 * Imai
 * Ken Yadanaka

Episodes
The following is a list of episodes featuring this part.
 * Rebirth
 * Confrontation
 * Dealings
 * Pursuit
 * Tactics
 * Unraveling
 * Overcast
 * Glare
 * Encounter
 * Doubt
 * Assault
 * Love
 * Confessions
 * Friend
 * Wager
 * Decision
 * Execution
 * Ally
 * Matsuda
 * Makeshift
 * Performance
 * Guidance
 * Frenzy
 * Revival
 * Silence

Chapters
The following is a list of chapters/volumes featuring this part.

Volume 1

 * Boredom (退屈, Taikutsu)
 * L
 * Family (家族, Kazoku)
 * Current (電流, Denryū)
 * Eyeballs (眼球, Gankyū)
 * Manipulation (操作, Sōsa)
 * Target (標的 Hyōteki)

Volume 2

 * Woman (女, Onna)
 * Slots (穴, Ana)
 * Confluence (合流, Gōryū)
 * One (一, Hitotsu)
 * God (神, Kami)
 * Countdown (秒読, Byōyomi)
 * Temptation (誘惑, Yūwaku)
 * Phone Call (電話, Denwa)
 * Handstand (逆立, Sakadachi)

Volume 3

 * Trash (芥, Gomi)
 * Gaze (視線, Shisen)
 * Humiliation (屈辱, Kutsujoku)
 * First Move (先手, Sente)
 * Duplicity (裏腹, Urahara)
 * Misfortune (不幸, Fukō)
 * Hard Run (激走, Gekisō)
 * Shield (盾, Tate)
 * Fool (馬鹿, Baka)

Volume 4

 * Reversal (転倒, Tentō)
 * Love (恋心, Koigokoro)
 * Judgement (判定, Hantei)
 * Weapon (武器, Buki)
 * Bomb (爆弾, Bakudan)
 * Easy (簡単, Kantan)
 * Gamble (賭, Kake)
 * Removal (移動, Idō)
 * Imprisonment (投身, Tōshin)

Volume 5

 * Whiteout (白紙, Hakushi)
 * Father and Son (親子, Oyako)
 * Eight (八人, Hachinin)
 * Strike (打撃, Dageki)
 * Separation (離別, Ribetsu)
 * Allies (仲間, Nakama)
 * Matsuda (松田)
 * Heaven (天国, Tengoku)
 * Black (黒, Kuro)

Volume 6

 * Successor (後継, Atotsugi)
 * Crazy (無茶, Mucha)
 * Ill-Suited (不向, Fumuki)
 * Impertinence (先走, Sakibashiri)
 * Give-and-Take (交換, Kōkan)
 * Potted Plant (植木, Ueki)
 * Yotsuba (四葉)
 * Misunderstanding (誤認, Gonin)
 * Split-Second (寸止, Sundome)

Volume 7

 * Scream (悲鳴, Himei)
 * Inside (中, Naka)
 * Creation (創造, Sōzō)
 * Embrace (抱擁, Hōyō)
 * Two Choices (二択, Nitaku)
 * Feelings Within (胸中, Kyōchū)
 * Zero (零, Zero)