Naoki Takeuchi is the protagonist of Majin Tensei II: Spiral Nemesis.
- Majin Tensei II: Spiral Nemesis: Protagonist
Naoki has short brown hair and blue eyes. He wears a baggy green padded jacket, jeans with one knee-pad, sneakers, and a headset. He carries a long sword.
Majin Tensei II: Spiral Nemesis
A member of the military group Partisan, he and his comrades attempt to fight the demons that have invaded Tokyo. Naoki is 23 years old. He is able to wield longswords, daggers, and guns.
Naoki's father was a scientist who worked for the government. He was a genius, capable of creating a time machine. He perishes in an explosion, and while the event was labeled an accident, Naoki believes his father was killed intentionally. Soon after his father's death, demons invade Tokyo in large quantities. To get his revenge, he joins the group Partisan, alongside his comrades Tomoharu Kikuchi and Kaoru Tachibana. He learns the man responsible for the demonic invasion is a mysterious man named Masakiyo Ogiwara, who has the power to control demons. Naoki learns of the demon summoning program, DIO, from a mysterious woman named Karen Rose in his dreams.
After the Partisan base is destroyed, Naoki runs into Tomoharu's younger sister Aya, and she becomes his ally. After finding her brother, she decides to join the team for good. Sometime after this, Naoki and his friends end up in the post-apocalyptic Tokyo of 2024, only to wind up in 1995 - the year before the demons invaded. Later, he and his friends will travel even further to the city of Megalopolis of 2052, the home of Karen. Depending on the player's choice, either Karen or Ogiwara (who turns out to be attempting to avert the crisis that destroyed Tokyo in 1996, and is from the world of Amnesia, a magical realm) will join.
Naoki's fate changes depending on the ending.
- Light-Law: he and the rest of the party return to the past and forget the mission they undertook to prevent a paradox from occurring. However, Karen is sent back as part of her next mission after she returns to her own time and meets Naoki after his parents call him to the lab regarding Karen's arrival.
- Light-Chaos: Naoki remains behind in the future to keep the peace, while the others pursue their own goals back in the past.
- Dark-Law: Everything seemed as if it was a vision and the ending just repeats the opening scene of Naoki's recruitment into Partisan.
- Dark-Chaos: Similar to the Light-Chaos ending in the regards that he remains in 2052 but with a slight difference.
Majin Tensei II: Spiral Nemesis
- The name Naoki is written in katakana (ナオキ), which has no special meaning. However, when written in kanji (直樹), it could possibly mean "straight, direct" (直) (nao) and "tree" (樹) (ki).
- Naoki's surname Takeuchi means "military, martial" (武) (take) and "inside, within" (内) (uchi).
|Main||Naoki Takeuchi - Karen Rose - Aya Kikuchi - Kaoru Tachibana - Tomoharu Kikuchi - Masakiyo Ogiwara|
|Minor||Bates - Dr. Takeuchi - Michael - Satan - Lucifer - Beelzebub - Raziel|
|Stage 1: 1996 AD Tokyo||Shibuya - Meguro - Laboratory - Ikebukuro - Shinjuku - Chigaya - Nagatacho - Invaders Base|
|Stage 2: 2024 AD Slum-Tokyo||Ueno - Asakusa - Korakuen - Shinjuku - Shinbashi - Subway Station - Ghost Station - Meguro - Laboratory|
|Stage 3: 1995 AD Tokyo||Meguro - Roppongi - Shinjuku - Ikebukuro - Korakuen - Ginza - Harumi - Shibaura - Shinagawa - Base|
|Stage 4: 2052 AD Megalopolis||Sidepolis-15 - Sidepolis-08 - Sidepolis-11 - Sidepolis-05 - North Junction - Corepolis - Supreme Council - Central Passage - Army CT-Room|
|Stage 5: Amnesia||Sabhas - Root-Amnesia - Syekahim - Rakia - Mahong - Ahlabot - Shamim - Zebr - Eden|
|Stage 6: Paranoia||Elleth - Root-Paranoia - Nesdia - Twia - Adhama - Tebel - Gee - Zebr - Cioule - Ahrqa|
|Terminology||Affinity - REMIX - Rank - DIO - Spiral Nemesis - Magnetite - FASS - Helios - Rag's Shop - Axis|
|Lists||Demons - Items - Skills|