|— Kumadori, CP9|
Seimei Kikan allows the user to completely control all of their body parts, even parts that cannot normally be controlled, such as hair. In such a case, the user can manipulate their hair to such a refined degree that they can actually wrap their hair around their opponent in order to bind them. The user's hair can even be shaped into the form of multiple hands which are just as versatile and prehensile as real hands.
The user can also control their involuntary functions, such as digestion. Kumadori demonstrates this when he was able to eat all the food within a giant refrigerator, digest all the food and most of his body fat in only a second, turning him super-skinny, then absorb all the nutrients in the food, turning him back to his original size.
Seimei Kikan, when used in conjunction with Kami-e, allows the user to manipulate their muscle mass. Rob Lucci used this ability in his half-leopard form to make himself smaller, thus making him faster and more maneuverable, at the cost of his brute strength.
- Kami Shibari (髪縛り Kami Shibari?, literally meaning "Hair Bind"): Kumadori lengthens his hair and manipulates it to bind his opponents. In the Viz Manga and Funimation dub, this is called Hair Bind. The term for this is a slight play on the term kanashibari (金縛り? lit. "gold binding"), which either is a term for sleep paralysis or "being tied down with money".
- Haru Gin Jo (春・吟・情 Haru Gin Jō?, literally meaning "Spring Poem of Passion"): After catching his opponent in Kami Shibari, Kumadori aims his staff at his opponent for a finishing blow. He attempted this at Nami, but Tony Tony Chopper punched him, causing him to lose his grip on Nami. In the Funimation dub, this is called Song of Spring Feeling.
- Yana Gin Jo (柳・吟・情 Yana Gin Jō?, literally meaning "Willow Poem of Passion"): Same as Haru Gin Jo, aside from the name. He attempted this at Chopper. In the Funimation dub, this is called Song of the Willow.
- Shoka, Kyushu (消化 吸収 Shōka, Kyūshū?, literally meaning "Digestion, Absorption"): Kumadori uses this technique to return to his normal size body fat after eating all the food in the refrigerator in which Chopper had locked him in. In the Viz Manga this is called Digest, Absorb.
- Shishi Shigan (獅子指銃 Shishi Shigan?, literally meaning "Lion Finger Gun): Rather than using his own fingers for Shigan, Kumadori shapes his hair into the form of hands and repeatedly uses the fingers of said hands to rapidly jab the opponent, similar to Lucci's Shigan "Madara", but less powerful. In the Viz Manga, this is called Shishi Finger Pistol.
- Seimei Kikan: Kami-e Bushin (生命帰還 紙絵武身 Seimei Kikan: Kami-e Bushin?, literally meaning "Life/Existence Return: Paper Drawing Martial Body"): Using Seimei Kikan, Lucci makes his half-leopard form smaller, lighter, and possibly increasing his speed. At any rate, he is much more agile in this form, and harder to hit - as opposed to his hulking normal half-leopard form. In One Piece: Unlimited Adventure (dubbed by Funimation), this is called Rebirth: Sketch Form, and in the Viz manga, this is called Life Return Paper Art Fighting Form.
- Seimei Kikan: Kaijo (生命帰還 解除 Seimei Kikan: Kaijo?, literally meaning "Life/Existence Return: Cancellation"): Lucci uses this while in his smaller half-leopard form. It cancels his Seimei Kikan: Kami-e Bushin technique, and returns to his larger, stronger half-leopard form. In the Viz Manga, this is called Life Return Release. In the Funimation dub, this is called Life Return: Terminate.
- Despite Kumadori's description of the Seimei Kikan implying that it takes 2000 years to master this technique, it is an exaggeration, as he was only 34 at the time, while Lucci was 28.
- For some reason in the anime, when Tony Tony Chopper roared in Monster Point, Kumadori could not control his hair temporarily and it froze where it was before returning to him; it was as though the roar frightened Kumadori or even the hair itself. Alternatively, he became distracted and subsequently his control failed.
- Other characters within the series have shown the capability of controlling their bodily functions similar to Seimei Kikan.
- Boa Sandersonia and Boa Marigold can both manipulate their hair into snake-like creatures;
- Speed Jiru appeared as a plump person at times, but slim at others. It is unknown if Jiru's abilities stem from Devil Fruit powers or not;
- Monkey D. Luffy has shown the ability to instantly digest and absorb vast quantities of food on several different occasions. While it is an ability similar to Life Return, this is actually the extent of his fruit, as he has not shown any conscious control of it and has not demonstrated any further use;
- Eustass Kid has been shown performing the same immediate digestion and absorption as Luffy.
- Lao G has showcased the non-Devil Fruit-related ability to recreate the strength he used to possess during his youth, giving the old man an exceedingly bulky physique (as opposed to his usual, frail-looking body).
- One Piece Manga and Anime — Vol. 42 Chapter 403 (p. 8) and Episode 287, The Seimei Kikan is first used.
- One Piece Manga and Anime — Vol. 44 Chapter 423 (p. 13) and Episode 306, Lucci activates Seimei Kikan: Kami-e Bushin.
- One Piece Manga and Anime — Vol. 42 Chapter 406 (p. 11-12) and Episode 290, Kumadori explains the Life Return to Chopper.
- One Piece Manga and Anime — Vol. 42 Chapter 406 (p. 19) and Episode 290.
- One Piece Manga and Anime — Vol. 42 Chapter 406 (p. 13) and Episode 290.
- One Piece Manga and Anime — Vol. 42 Chapter 403 (p. 9) and Episode 287.
- One Piece Manga and Anime — Vol. 42 Chapter 407 (p. 9-11) and Episode 290.
- One Piece Manga and Anime — Vol. 44 Chapter 427 (p. 9) and Episode 309, Rob Lucci uses Seimei Kikan: Kaijo to revert to his previous form.
- Biofeedback – Wikipedia article on the concept Life Return is based on.