"Gen. You betrayed me once. Yes, my greatest error was reviving you. Or so I thought... Now I'm glad to have you around."
Ironically, he is the kind of person whom Tsukasa wished to not revive: a greedy man who cares only about his own desires. However, Tsukasa was desperate for a brilliant mind like Senku's to help him. Gen later becomes one of the Five Wise Commanders.
As one of the Five Wise Commanders, Gen is the most strategic about how to carry out missions, often finding ways to avoid labor if he can. When it comes to enemies, Gen acts as a tactical forecaster. Kaseki tends to drag him along to help with crafting if Chrome is busy with Senku.
Gen is a slim young man, close to Senku in height, but taller. His hair is split, with the left half being short and black and the right half being white with longer strands around his face; prior to his petrification, all of his hair was black, but it was already partially white before becoming petrified. His eyes are baggy and have a jagged stone mark running down his left eye in an angled line. This line varies in appearance depending on what Gen is doing, such as becoming flower-like when mimicking a woman's voice or extra jagged while scheming His petrification scar is healed by his second depetrification. After Tsukasa's revival, he used paint to recreate his scar.
He wears an overcoat over a yukata and lacks proper footwear.
Later, Gen replaces his outfit with a similar overcoat over a yukata, but rather than it being laced up at the front of his neck, it's tied with a necktie, and his sash is a piece of fabric rather than rope. He also wears sack-like shoes, similar to Senku's original ones.
Gen is somewhat full of himself and his abilities, taking pride in his status as a magician and a mentalist/psychologist, along with his knowledge of the human psyche. He is outwardly stoic, staying calm even when at spearpoint when he first arrives at Ishigami Village. However, this facade seems easily broken through, as seen at his shock when Senku addresses him by name. Despite this, he is revealed to be extremely paranoid (though rightfully so), hiding multiple bags of blood in his clothes in the event he is attacked. He has shown signs of perversion, considering sticking by Tsukasa for the purpose of having a harem and hitting on Kohaku and later Amaryllis. Regardless, Gen is rather quirky and can often be seen speaking in Pig Latin; his most common verbal tic when shocked. He tends to be self absorbed, and perverted; though he gives off gentlemanly air even when being honest about such. He also shows reluctance in participating in the manual labor involved in Senku's experiments (though given how arduous the labor is, it is understandable). In addition, as stated by Kohaku in his introduction, he is perfectly capable of lying without a hint of stress or change in expression.
While not nearly as intelligent in terms of science compared to Senku, he proves to be his equal and one of his most vital allies due to his ability to understand the human psyche and manipulate people through lies in contrast to Senku's more honest nature. He uses his abilities to promote cooperation and enthusiasm, motivate allies, conduct negotiations, and outsmart enemies. He tends to shift between acting as a ditzy airhead when it suits him (such as to avoid work or going into battle) and an intelligent manipulator. He is confident and is shown to have nerves of steel, even in the face of death.
He is a proud turncoat, openly offering to lie to Tsukasa about Senku's death when he sees his kiln. Gen favors being on the "winning side," although he is also easily swayed by Senku promising him something that appeals to his personal interest. Despite this, he later admits to Senku that he was most likely already won over by Senku's intelligence and ability to move mankind forward. He proves to be loyal to Senku and uses his abilities to help further Senku's plans usually by manipulating people such as promising Minami a special present to get her to relinquish the last bit of the de-petrification potion she had to revive Francois and similarly tricking Ryusui into paying a ridiculous amount of money to board the hot air balloon (though they needed him to board due to his excellent piloting skills).
He shows a surprisingly strong will and level of endurance, being able to survive a death attack from Magma with proper preparation and still go to the Tsukasa Empire gravely injured to report Senku's death. He was also barely able to keep up with Francois walking to the Ishigami village two days straight (a rather difficult feat without food, water, or shoes).
While he frequently portrays an aura of selfishness, hard self-interest, manipulation and deviousness, Gen is intrinsically a good person who can't bring himself to harm others. His outward appearance is masked by his mastery in psychology, but his actions tell of loyalty, determination, kindness and even sacrifice at times.
He is more than capable of genuine kindness, at one point creating a telescope as a surprise birthday present for Senku. He also seems to get along decently well with Suika, a child. He seems to not hold grudges, as he is able to work with Magma and manipulate him without fear, despite Magma having once attempted to murder him. In addition, he is also quite genuine in his admiration of others, respectfully recounting Lillian Weinberg's renowned singing skills to the people of Ishigami village in reverential tones. This was likely to inspire them further to ally themselves with Senku's goal of bringing back civilization as well as to boost their morale by bringing to their awareness of how esteemed their ancestor was in the pre-petrification world.
On a side note, he has frequently stated that his favorite drink is cola and that he doesn't drink alcohol.
Psychology: As a mentalist, he is deeply perceptive and manipulative, having a large knowledge of the human psyche. He is capable of analyzing and understanding obscure messages or drawings with his great knowledge about the human mind; he was able to decipher Kohaku's message by understanding what each image represented from her point of view. Gen is also able to "put [himself] in the mind[s] of [others]", correctly figuring out what they are thinking or planning. Gen is very crafty, as he anticipated being attacked and created fake blood packs to wear for a visual trick and to soften blows to his body. This saved him from being killed by Magma.
- Skilled Liar: Gen is an expert liar, as he can fool anyone. When it comes to the post-petrification humans, Gen can easily impress and trick them into believing his tall tales. Though he is equally good at manipulating people from his era (minus Senku, whom he often collaborates with in these cases) with his showmanship. Gen has stated that the best trick of a mentalist is to "make your joker look like the ace of spades". He was also able to fool a polygraph test, with only half-truths. This left Dr. Xeno amazed, even when the scientist suspected Gen of lying.
- Manipulation: Gen has three steps to manipulate someone into working for his goals, should the person be strong-willed and therefore hard to trick (like Moz). 1) Stand by them to build a sense of comradery; standing across from them makes the conversation feel adversarial. 2) Give inaccurate information relevant to the conversation; it will force the target to correct you and give up the correct information. 3) Order them to do the opposite of what you want them to do. Human beings naturally refuse an order by nature, choosing to do the opposite. His manipulation tactics are quickly seen when he goads Kinro and Ginro into helping Senku power-up an electricity generator.
- Stage Magic: Gen is a master of sleight of hand. He also keeps various props hidden within his coat, so he may cause distractions or fake "peace offerings" to buy time. He makes use of this immediately after arriving into the village, distracting the hostile villagers planning to attack Senku.
- Impersonation: He also makes for a very convincing female if the need to disguise himself comes up, with Kohaku stating that his only flaw was that he was too tall for a convincing woman. He is capable of mimicking people's voices to the point of being indiscernible from the original.
- Linguistic Proficiency: He seems to be fluent in both Japanese and English. He was able to understand Ukyo when he was speaking English through the buried phone in order to conceal their conversation from the others present and offered Senku to take over the negotiation (Chapter 73). He was able to speak to both Stanley Snyder and Dr. Xeno with no problems.
- Gen's last name, "Asagiri" (あさぎり), translates to morning mist/fog. His first name is the Japanese word for "illusion", a reference to his penchant for magic.
- Gen has a low tolerance for alcohol.
- Since the recreation of paper, Gen keeps a deck of crudely made cards with him all the time.
- In addition to the normal 52 cards, he has three jokers.
- Each joker has a phrase on it, but it's unknown if the other cards do as well.
- It's possible Gen knows tarot, hence the phrases.
- Gen's poster can be seen on a book called "Magic Psychology", prior to the petrification event.
- Gen's first petrification happened while posing on a box full of swords he escaped from during a performance.
- Similar to Senku's hair color, Gen's hair color has varied throughout the series. It appearing as blonde and blue (Chapter 66 Dr. Stone Character Poll), white and brown (Chapter 25 and 104 colour pages) and blonde and brown (Chapter 95 and 111 color pages, Shonen Jump Issue 31 2019, and the Viz Shonen Jump Banner of July 2019). In the anime, his hair is white and black.
- Gen ranked 3rd in the 1st and 2nd Character Popularity Polls and placed 1st in the 3rd Character Popularity poll.
- Gen's verbal quirk is to flip the halves of random words. For example, "yabe" (やべ) becomes "beya" (べや) or "muri" (無理) becomes "rimu" (理無). In the English translations, this has been replaced with pig latin where he most notably uses it to describe Senku's crazy plans as "azy-cray".
- Gen's heterochromatic hair might be caused by a condition named "poliosis", which causes a decrease or absense of melanin in affected hairy areas. This would explain why it became/remains discolored after depetrification, as well as suggest that he dyed his hair fully prior to the story's events. This is supported by the poster on the book "Magic Psychology" where Gen's hair is fully black.
- Gen's English voice actor is the real life husband of Magma's voice actor.
- Gen and Senku share opposite birthdays, his being on the 01/04 (April 1st), and Senku’s being on the 04/01 (January 4th).
- Gen's scar completely vanishes after the South America arc as he stops drawing it back on, which Boichi notes to have been on purpose.
|Male||Chrome • Gen Asagiri • Ginro • Hyoga • Joel Gear • Kaseki • Kinro • Kokuyo • Magma • Matsukaze • Moz • Ryusui Nanami • Sai Nanami • Senku Ishigami • Taiju Oki • Tetsuya Kinomoto • Tsukasa Shishio • Ukyo Saionji • Yo Uei|
|Female||Chelsea Childe • Homura Momiji • Kirisame • Kohaku • Minami Hokutozai • Mirai Shishio • Nikki Hanada • Ruri • Suika • Yuzuriha Ogawa|
|Unknown||Francois • American Colony • Ishigami Village|
|Male||Brody Dudley • Byakuya Ishigami • Carlos Barrios • Gen Asagiri • Hyoga • Joel Gear • Leonard Maxwell • Max Adams • Ryusui Nanami • Sai Nanami • Senku Ishigami • Shamil Volkov • Stanley Snyder • Taiju Oki • Tetsuya Kinomoto • Tsukasa Shishio • Ukyo Saionji • Xeno Houston Wingfield • Yakov Nikitin • Yo Uei|
|Female||Charlotte Bony • Chelsea Childe • Connie Lee • Darya Nikitina • Homura Momiji • Lillian Weinberg • Luna Wright • Maya Biggs • Minami Hokutozai • Mirai Shishio • Nikki Hanada • Yuzuriha Ogawa|