Takashi has dusty-blonde hair (silver hair in the manga), golden-brown eyes with slit irises (green eyes in the manga) and he usually seen with a soft smile (noted on several to occasionally be fake). He is currently around 167 cm in height.
He is often mistaken for Reiko Natsume (Takashi's grandmother), by youkai, making him a constant target of youkai who had a history with Reiko.  Similarly, Takashi has also been considered to be a bishounen (a.k.a beautiful boy) by many and has multiple fan girls in his school . However, he seems to be oblivious to his appearance and his admirers, much to the disbelief of Atsushi Kitamoto and Satoru Nishimura.
It was revealed in the Official Fanbook that Takashi has a complex about his feminine appearance and consciously makes an effort to be masculine by using manly language (Natsume uses "ore", the masculine version of "I" in Japanese, instead of "boku" or "watashi", which is more polite).
Unlike Reiko Natsume (Takashi's grandmother), Takashi is a kind boy to both humans and youkai, to the point that he is easily fooled by them as mentioned by Tsubame.  Prior to the beginning of the series, he was originally reserved and soft-spoken because of his troubled past and used to greatly dislike having the ability to see youkai because of the trouble it's given him. Because of his reservedness he's had trouble interacting with other humans.
Thanks to the kindness of Shigeru Fujiwara and Touko Fujiwara, Atsushi Kitamoto, Satoru Nishimura and his friendship with Madara, Takashi slowly opens up to both humans and youkai. However, he does occasionally suffer slight trauma from his past, often in a dream or when he sees humans (usually exorcists) acting despicable. One of his wish as a child was to grow up and live independently, away from everyone else.
Takashi does not reveal his ability of seeing youkai to the Fujiwara couple, nor Kitamoto and Nishimura (Takashi's friends), because he's worries that they would stop being normal for constantly worrying about him. He also tries to hide what he sees from Kaname Tanuma because he is worried that he may drag him into his problems. The author describes him as, "a person who try his best to be kind".
Though Takashi has seen youkai all his life, he has little tolerance for their antics. When angered or pushed, he lashes out in a punch or a kick of resistance, which has enough spiritual energy to knock even the highest level of youkai out in a second.
However, his fighting abilities only extend to youkai; his punches, as noted by Madara, do not work on humans. Takashi is very agile and good at climbing trees because he was always running away from youkai. He has short stamina (constantly mentioned by Nishimura) and is very susceptible to heat.
Takashi's mother died after he was born so he has no memories of her. Even though his father did raise him, it was only for a brief moment and thus he also has very little memories of his father. The only memory that Takashi has of his father is when they lived together inside the Natsume household. He remembered that his house had a chime and his father would often spend time with him at their backyard. While there, his father would tell him about the flowers that his mother planted before she died and would wish for them to bloom. As a child, Takashi would often draw on the walls for fun, making him quite a mischievous boy before he became an orphan.
After Takashi's father died, Takashi was forced to be passed around by his relatives. Being the only person around who can see youkai, Takashi's actions became overly strange to everyone around him. His classmates and his relatives begun to ostracize him under the assumption that he's lying to get attention from everyone. He's even been sent to an orphanage but was expel for scaring other children with his behavior  No matter where Takashi goes, he seems to become nothing but a target of bullying for both humans and youkai alike. One of the classmate who bullied Takashi as a child is Katsumi Shibata.
One of the very first family that Natsume came under was the household of the Aoi couple. They have a daughter name Miyoko Aoi who is also around Takashi's age, but even though he was treated well by the couple, Miyoko hated Takashi and wanted him to leave. Miyoko, who couldn't see youkai, accused Takashi of stealing her parents attention away by lying. Takashi, who is still only a child, wasn't able to do anything to resolve the problem and Miyoko's hatred towards him continues to escalate.
After an incident involving Takashi, Miyoko angrily lash out at Takashi, forcing Takashi to run away. Takashi, while running, attempt to return to his home where him and his father once lived. But being only a child, Takashi neither have the strength nor knowledge to reach his house. After calling for his father over and over again in the dead of night, Takashi decided that from that day forward, he will not call out to his father anymore. Cause no matter how much he cry for his father, he now knows that his father will never answer.
After the Aoi couple, one of the relative that Takashi went to next was a family who lived near The Tree Youkai. There, Takashi encountered the Tree Youkai who scared away the classmates that was bullying him. After realizes that Takashi can see her, she becomes interested in Takashi. In attempt to connect with Takashi, the Tree Youkai constantly try to scare Takashi. Takashi, who couldn't understand her, decided to asks her why she spend so much time with him. Embarrassed, the Tree Youkai replied that she didn't care for Takashi and is only doing it because she hates humans. Takashi, who is still a child, took what she said as her true feelings and sadly smile has he walk away.
The Tree Yokai was happy for being able to talk to Takashi, yet displease that he took her words so heavily. Thinking that Takashi will talk to her again if she continue to tease him, the Tree Youkai try to scare Natsume the next day like she always do. But to her dismay, she not only causes Takashi to fall but a classmate who was warming up to Takashi to fall as well. Realizing that she just cost Takashi a friend, she tried to apologize but it was already too late. Angry and filled with sadness, Takashi yell out to the Tree Youkai, saying that he hates her and yield at her to go away. After the incident, Takashi decided to take the longer path to school and avoided the Tree Yokai completely
Feeling guilty and wanting to apologize to Takashi, the Tree Youkai turned into a cat in order to seek him out. After searching for some time, she finally found Takashi sitting alone in a grass field while staring at the sunset. Not knowing that the cat is the Tree Youkai, Takashi gentle took the cat into his arms and told her his wish to be alone and independent. Hearing his wish, The Tree Youkai silently cried in his arms, lamenting that if anything, being alone is sad and lonely. The day after, due to family situations, Natsume was moved to another family in a different town.
One of the next relative that Takashi went to was a shady couple who live in a small town out in the countryside. There, he met with a girl classmate name Yuriko Ogata who he unintentionally kick out of fear of the Yokai who was after him. Angry, Yuriko quickly approach Takashi and demanded an explanation. Takashi lied and told her that he had a bad dream and was startled by her. Noticing that Takashi hair was quite long, Yuriko carelessly made a comment about it. Takashi reply that he'd cut it himself. Yuriko, who thought that he was joking, made fun of Takashi. To which Takashi replied it's not like he can ask his foster parents for money to cut it.
Realizing that she just unintentional ridicule Takashi, Yuriko felt guilt and try to look for a chance to apologize. But due to Takashi's demeanor at school, she couldn't bring herself to. That is until Takashi offer Yuriko a place under his umbrella during a raining day. While walking home with Takashi, Yuriko manage to build up enough courage to apologize. But Takashi told her that she had nothing to apologize for. Realizing that Takashi is actually a kind person and nothing like the rumor she heard, Yuriko became acquainted with Natsume.
That is until the Yokai that came after Takshi broke the windows at school. Not being able to see the Yokai, everyone blame Takashi for it. Everyone but Yuriko. She tried to argue that the culprit was not Takashi. But in order to not get her involve, Takashi thank her and told her to stop vouching for him. After the incident, it was decided that Takashi will be moved to another family. He met one last time with Yuriko and lament that no matter where he goes, he always end up getting hated by humans and Youkai. Yuriko, then told Takashi that he wasn't hated that at least she didn't hate him. Takashi smiled and say that his stay there was actually fun thanks to her.
One of the next family that Takashi was sent to is his aunt and uncle who lived with their son. There, he met the Long Haired One-Eyed Youkai, who saved him from another youkai. After finding interest in his loneliness, the Long Haired One-Eyed Youka decided that she want to take Takashi as a human pet and told Takashi to leave his relative behind. Takashi, who has been introduce to the Fujiwara couple, didn't want them to get involve and decided to seal the Long Haired One-Eyed Youkai before she hurts anyone. After some struggle, Takashi was able to seal the youkai away. But in doing so, he fell off a high cliff and was heavily injured. Realizing that he can no longer stay with his aunt and uncle, Takashi decided to take up on the Fujiwara couple's offer of adopting him. And thus, Natsume became the foster son of Touko and Shigeru Fujiwara.
Natsume moved to the city of Yatsuhara, becoming a sophomore at the local Yowake High School. One day he is attacked by two youkais who mistaken him for Reiko, his grandmother. He is uncertain as to why and tries to reach the local shrine but before he could make it, Hishigaki grabs ahold of him, he is demanded to return her name and almost suffocates him until Natsume strikes her in the eye. He escapes from her clutches and continues running but accidentally rips through a binding rope. A deep, powerful voice is heard and Natsume fears for his life until the small shrine doors open and what's inside is... a maneki neko... Natsume laughs because this was where the powerful voice came from. But the maneki neko shatters the tiny shrine he was sealed in and when Natsume is unresponsive, the maneki neko prompts him to speak. Natsume answers he's used to it. Then the maneki neko realizes he is Reiko but Natsume explains he is her grandson. That is when the maneki neko tells him what he knows about her: she was lonely due to her ability to youkai, she was ostratized and so she began to interact with youkai. That is when Natsume is asked if he had heard about the Book of Friends. He affirms he does only to have the maneki neko disappear as soon as he answered. He returns home and recounts that the Fujiwara were the kind couple who took him in. He states that he wants to ensure their happiness and hides his abilities from them. He notes that he still is not sure how to act around them but maintains politeness, and is very grateful to them. In his room, he searches for the Book of Friends and when he finally finds it, the maneki neko from before had followed him and demanded he hand it over. Natsume dodges but the maneki neko gets stuck in the wall. With Touko out shopping, Natsume gets more information about the book from the maneki neko, who tells him to call him "Nyanko-sensei". Nyanko-sensei that this book contains the names of all the youkai who had lost a game to Reiko. This is a life-binding contract and whoever holds their names would be at their every beckon call. Should anything happen to the names on the paper it will affect the actual youkai itself. Natsume wants to keep this book because it belonged to his grandmother. He wants to return all the names in this book but Sensei still wants it so he decides to stay with him as Natsume promises that should he die in the process of returning the names, he may have the book. In return, Sensei will protect him (which he often "forgets" to or outright allows Natsume to be hurt) until then. The book has given Natsume trouble from time to time but he also is grateful because he is able to meet various youkai and forge everlasting companionships, both with youkai and humans.
Because the Fujiwara couple took him in their home and treated him with kindness, Takashi works hard to ensure that they don't know about his abilities to speak with youkai since he tries not to trouble them in any way.
Although he is not their own child, they treat Takashi as if he was their own. Takashi hopes to pay them back for their kindness one day, yet he wonders if he would be ever able to repay their kindness.
- Main article: Reiko Natsume
Reiko Natsume was Takashi's grandmother (from his mother's side). Sadly, Takashi never met or knewn his grandmother (as she died young), well long before Takashi was born. But through the Book of Friends (giving youkai their names back), Takashi slowly learns what kind of person, his grandmother was and he hopes he'll learn who his grandfather is.
- Main article: Madara
Nyanko-sensei is Takashi self-proclaimed bodyguard, though he often blatantly ignores when Takashi is in danger and instead drinks sake or chases around with insects or even sleeps. Furthermore, he tried to eat Takashi several times during the beginning of the series.
Madara claims that he will only stick with Takashi until he dies so that he would get the Book of Friends. However, there are occasional times when he would forget that promise, such as the time where he said it was a pity that Takashi had not drank any mermaid's blood after meeting one, and Natsume laughs and says, "But then you'd never get the Book of Friends, would you?" which causes Nyanko-sensei to lapse into silence.
He also becomes furious when others, especially Matoba, try to harm Takashi. Though they argue a lot, their relationship is similar to that of a grouchy but over-protective uncle and an exasperated but loving and appreciative nephew.
- Main article: Kaname Tanuma
He is one of Takashi's schoolmates and friends. Tanuma also has the ability to see youkai, but on a much weaker level, only being able to sense their presence or see their shadows. He can also hear them on very few occasions. Initially, they see each other as comrades of the same boat in detecting youkai, but soon the great difference in abilities made Tanuma upset since he cannot help Takashi much with youkai.
Takashi is very protective of Tanuma because he knows that, likewise, Tanuma is protective of Takashi. Takashi knows that Tanuma will help him no matter what the cost, and that scares him because he does not want Tanuma to recklessly protect him and get hurt. Takashi is reluctant to share his vivid experiences with youkai as well, because he knows that Tanuma cannot relate and will feel guilty about not being able to do so.
In the episode The Gap Between Humans and Youkai, Tanuma has a breakdown and confesses that he's scared of being useless and losing Takashi's friendship in the process. He knows that Takashi is keeping secrets out of kindness, but he doesn't want a wall between them because of it. Takashi promises to tell him more from then on, strengthening their friendship. Soon after that, in the beginning of season 4, Takashi starts to rely more on Tanuma and Taki with his youkai problems and is more open to discuss solutions.
- Main article: Tooru Taki
Another of Takashi's friends and classmates who know his secret. Taki is a descendent of an onmyoji and has the ability to inscribe magic circles to see youkai. Other than that, she is an ordinary, energetic girl who loves cute things (though her range of 'cute' extends to Madara as well).
Like Tanuma, she tries to help Takashi any way she can, but she is often prevented because Takashi does not want her to be involved with his problems. Takashi's friend, Nishimura, has a crush on Taki, though most of her attention is devoted to Takashi.
In the beginning of season 4, Takashi begins to rely on her a lot more along with Tanuma. Taki also gives support with her onmyoji knowledge through her growing passion in learning from her grandfather's books such as creating tailsmans.
Kitamoto Atsushi and Nishimura Satoru
Takashi's two best friends were the first to call out to him. They are very close, to the point that Takashi sometimes tells them about his troubled childhood or has meaningless squabbles with them, and they are both understanding and tolerant of his occasionally strange behavior (which usually involves youkai).
When Takashi hurts himself by accident (again, usually involving youkai), they lecture him and remind him that he can tell them anything. Takashi does not mention his ability to see youkai because, like with the Fujiwara couple, he is scared that they will no longer treat him normally.
- Main article: Shuuichi Natori
Natori originally took interest in Takashi's strong spiritual power (which Natori hints is even stronger than his own) and wanted Takashi to be his apprentice in exorcism. Takashi refused because the way they see youkai is different; Natori sees youkai as both tools and dangerous, while Takashi treats them with kindness and sees them as an equal (no difference from human).
However, their relationship gradually becomes brotherly, to the point where they can rely on each other for help. Natori asks Takashi to go to a hot spring with him on a vacation (although it should be noted that Natori initially wanted to go to check up on a sealed youkai there). Natori also offers to give Takashi a place to stay if he "ever gets tired of telling lies", meaning lying to the Fujiwara couple about his ability. Natori calls Takashi his one friend who is able to see the same scenery.
- Main article: Seiji Matoba
One of Takashi's more obvious enemies. Matoba is a cold-hearted exorcist who, like Natori, wants Takashi to become an exorcist, as well as to join the Matoba clan. Takashi initially dislikes him greatly because Matoba thinks nothing of hurting or enslaving youkai to do his bidding.
He also seems to show no empathy towards other humans. After learning of Matoba's loneliness and sacrificial position, however, Natsume softens up slightly towards him, but he still refuses to join the Matoba clan.
- Main article: Jun Sasada
While the two are not particularly close, Sasada suspects Takashi of being able to see youkai because she herself met one and wanted to meet it again. Sasada had observed Takashi and noted his quirky behavior, thus drawing out the conclusion that Takashi could see things no one else could see.
She is similar to Takashi as to having no close relatives: her mother died and her father remarried, then her father died and her stepmother also remarried. In the manga, Sasada moves away and is never seen again.
In the anime, she stays as one of Takashi's class representatives and it is often implied that she has a crush on him.
- Main article: Katsumi Shibata
- Main article: Yuriko Ogata
Powers & Abilities
- Returning Names: Being Reiko Natsume's descendant, Takashi can return the names inscribed in the Book of Friends, thus freeing the youkai his grandmother originally bounded. He does this by first picturing the youkai in his mind, which the book reacts to by flipping to the page the name is written on. Takashi then rips out the page and places it in his mouth, as the ritual requires either the blood or saliva of the owner. He then claps his hands and exhales. The cost of releasing the name, however, drains him of a lot of energy in the process, and he often becomes very tired afterwards.
- Dream/Memory Reader: If a youkai becomes emotionally unstable in the same space as a sleeping Takashi, its dreams may flow into Takashi's. On the other hand, most of the youkai let Takashi see their memories so that he can understand their situation better. Takashi can also see their memories when he releases a youkai's name.
- Spiritual Power/Fighting Ability: Due to being directly related to Reiko, he has strong spiritual power, which allows him to see and hear youkai that are normally intangible and invisible to other humans. He can also interact with youkai, and vice versa. Takashi's strong spiritual power are also significantly effective, as shown when he punches Madara and other youkai, and often knocks them unconscious. His incredibly strong ability in spiritual magic and strength causes him to smell delicious to man-eating youkai, according to Madara, and draws in unwanted attention from hostile youkai. However, Takeshi does not use his powers for any other use than returning names, even though he hits and hurts youkai with some of his power. In later episodes, he develops the ability to sense the presence of nearby youkai when he is given enough time to focus.
- Sealing/Spells: In episode 38, Takashi has had minor experience with sealing spells before as seen in his younger years. Shuuichi Natori had also expressed intrigue at Takashi's spiritual ability, being impressed that Takashi could animate a paper doll to find a youkai on his first try so quickly.
- Takashi's surname Natsume means "summer eye" in Japanese.
- Takashi seems to be the only human (besides Reiko Natsume), to be able to read the names in Book of Friends. (However, both Natori and Matoba have not tried to read and the guide book states that anyone with spiritual power could read it.)
- In the manga, Takashi has silver hair and green eyes. In the anime, however, his eyes were changed to golden brown. In the anime he is less irritable than in the manga; he is more relaxed.
- Takashi appears to have some sewing skills, as shown when he sewed clothes for the baby chick Tatsumi. However, later on during the school festival, Takashi was tasked with being the cashier for the class bazaar and he seemed to have some difficulty sewing up the pink ribbon onto his apron.
- Takashi has a complex of being weak and having a feminine face, so he consciously tries to act masculine and use tough language.
- Although Takashi always sleeps in class and he is frequently absent, he is quite popular with the girls at school. 
- Takashi is bad with children (due to his own troubled childhood). 
- Takashi is only the human member of The Dog's Circle.
- Takashi dislikes parsley.
- As stated in the manga, Takashi likes street punk clothes despite normally wearing his school uniform of collared shirts in the Summer.