Senku Ishigami

Senku wholeheartedly believes in science and is confident that there is nothing science cannot solve, even if it takes science a long time to understand. Although Ishigami has a strong sense of justice, he often bends the rules, withholds information, and manipulates others to get what he wants, but only for the benefit of his allies. Senku often appears to exploit others for his own gain and for the sake of his inventions (glasses, glass, and so on), but beneath his arrogance and manipulative nature lies a genuinely kind nature. When asked who he would choose to save—himself, a friend, or his lover—Ishigami replied that he would find a way to save everyone. His actions have repeatedly shown that he is willing to sacrifice his own interests for the sake of others. Unlike Taiju, Senku is far from the idea of ​​romance and dislikes it. He seemed dismayed when Kohaku gave him the odd compliment of "falling in love with him" (she explained that she liked him as a person, whereas before, she thought he was a "woman killer"). He believes that a brain filled with love is the most illogical, but he supports his friends in their relationships, such as Taiju with Yuzuriha or Chrome with Ruri (even though the two can't admit their feelings). Despite all this, Gen believes that one day, after he completes the creation of civilization, he will consider the idea of ​​romance. Fun fact: before his petrification, Senku always saw Gen on TV, as Gen was a fairly popular mentalist, but after his petrification, Gen is now in front of Senku 24/7, which sometimes irritates him.

Senku is known for his catchphrases, one of which is "Ten billion percent." He emerged from petrification six months before Taiju and eventually created the stone formula with Taiju's help. In the stone world, Senku seeks to restore civilization and create a Kingdom of Science. He became a champion of the village games and currently holds the title of village chieftain in Ishigami Village, where he was widely known thanks to the influence of Byakuya, the village founder, who passed down Senku's tale through generations. Senku is a slender young man of average height with unruly, light-green hair that sticks up. Two long strands fall over his face. His eyes are a vibrant red. His stone markings are two symmetrical diagonal lines running from the base of his eyebrows across his forehead. Kohaku calls him a "ladies' man," implying that he is handsome. Before the Stone Apocalypse, he wore a typical school uniform with a lab coat over it. After waking up in the Stone World, he began wearing simple clothing made from animal skins. His clothing was later slightly modified by Yuzuriha. On the collar of Senku's shirt is Einstein's energy formula (E = mc²), written in his own blood. Senku is a straightforward, confident, and very logical person who can come across as arrogant. Despite this, his overconfidence doesn't cloud his judgment, as it is often backed by his superior and extensive knowledge of science. Senku never belittles those less intelligent than him. On the contrary, he encourages and inspires those around him, making them unconsciously do better. Because of his charisma and caring nature, people tend to flock to him as allies and supporters. However, he can go overboard when he's passionate about creating or discovering something new. Senku is full of confidence, despite being trapped in a stone world.

Furthermore, Senku hasn't mastered the task of making glassware, and for more detailed and intricate items, he requires skilled artisans like Kaseki to craft them. He also requires Yuzuriha to assemble broken stone statues, as he lacks her talent and precision. While not a weakness per se, Senku isn't an exceptional cook. He can cook, but he lacks experience and quality ingredients. Although he knows the process of cooking, more complex foods often don't taste good. While he can make cotton candy and cola, more complex foods like wine, ramen, and bread turned out to be terrible. The ramen incident, however, was partly due to a lack of precise ingredients (he used foxtail flour instead of wheat). When he first tried to make bread with all the right ingredients on hand, it turned out so terrible that no modern human could eat it (though the Ishigami village liked it, as they previously ate only fish and had never tried bread). Senku is allergic to lacquer, which causes his face and lips to swell dramatically. Throughout the series, despite his high intelligence and ability to overcome obstacles, he often gets into trouble due to his terrible luck. Gen at one point jokes about Senku (when they tried to make gunpowder to stop Tsukasa's army and failed) that Senku is always unlucky. Due to Senku's focus on rebuilding civilization, as well as his aversion to romance, he has trouble with romantic relationships. He has three main phrases: he says "10 billion percent" when he is sure of something, "1 mm" when he states how impossible something is, and "This is so exciting" when he makes a new discovery or succeeds in furthering his scientific research.

Senku Ishigami is a genius with an encyclopedic knowledge of all things scientific. He is well-versed in chemistry, physics, engineering, geology, biology, and mathematics. Despite the limited materials in the Stone World, Senku is able to easily create various useful tools and devices, medicines, and most importantly, a depetrification elixir. Tsukasa calls him "the most insightful, most intelligent person in the world." In addition to his scientific knowledge, Senku also possesses resourcefulness and an analytical mind. Senku is able to think on his feet and maintain composure in the most dire situations. Although arrogant and eccentric, Senku seems to have a keen understanding of people and how they think. He uses his numerous creations to charm those who are suspicious of him (such as ramen, glasses, and medicine), warming their hearts to him. Senku is also a capable leader, eloquent, able to motivate and transform the villagers into an effective army against the Tsukasa Empire. He has earned the loyalty and respect of his allies (and enemies) through his hard work and determination. Senku is below average in physical ability, lacking in strength. He was unable to restrain Homura, a petite woman under 5 feet tall, after he managed to grab her. He also admitted that he wouldn't stand a chance against someone as strong as Kohaku in a fight (though this isn't entirely a fair comparison, given how strong she is). Senku also has poor stamina and tends to tire physically quite quickly. He is also very vulnerable to hypothermia, only being able to withstand cold water for short periods of time. While adept at craftsmanship, he lacks natural talent. It took him several months to learn pottery making, and even then, it could only be considered decent.