Tsukasa Shishio is the leader of the Empire of Might, His goal is to thin out the human population in order to create a new world without modern technology, saying that adults and how humanity evolved caused them to become evil.
Despite his claims that no threat would come after Senku and Taiju, which proved ironic, Tsukasa became one of the biggest obstacles to Senku's Kingdom of Science and restoring humanity as a whole in general.
Tsukasa is a tall and muscular young man with wild, brown hair that he has been growing since childhood with bits of stone near the ends, and pale skin. He has an androgynous face, and is stated to be handsome by Minami Hokutozai. His height is estimated to be somewhere around 203.8 cm/6'8".
He has three stone markings: one across his face that cuts across his right eye, another etched deep into his left one from the corner of his eyelid all the way down across his nose and ends at the bottom of his jaw on the right, and the third being stretched across from his left shoulder over his chest and stopping at his upper abdomen.
After years of MMA fighting, Tsukasa gained permanently swollen knuckles on his index, middle and ring fingers.
His initial outfit is a crude red yukata and cloak made from a lion that he killed to protect Senku and Taiju. He used its pelt as a coat that he wore around or draped across his shoulders. He wears no shoes. Once he meets Senku after a year after believing he had killed him, he wears a cream pelt shirt with his torn yukata as a skirt.
Tsukasa is essentially violent, but extremely careful and aware of his actions. He is a very kind, thoughtful, and polite man outside of his pessimistic ideals towards humanity. He offers help in the beginning to Senku and Taiju after they revive him and becomes their hunter for food, using his skills as a prominent athlete to aid them. It’s revealed later that Tsukasa plans to purge humanity and thinks Senku will go along with him, but instead Senku rejects him. After this point, Tsukasa becomes fairly determined in carrying out his plans even to the point of leaving their group. He’s confessed to Senku that he doesn’t care about anyone but himself, though in the latter half of the story, it’s revealed that Tsukasa loves his sister Mirai more than anything in the world and that is where his resilience comes from, so he can save her.
He also reveals that Senku could’ve been his first friend pre-petrification, to which Senku agrees. From this angle, we can assume Tsukasa shuts himself off from others and only focuses on saving his sister. He’s naturally withdrawn outside of his goals. He tends to hate humans who control and manipulate others. By his actions, it is possible to assume that Tsukasa hates any hierarchy or practice of power. His goal is to create a society without technological advancement and he uses any means to achieve that objective; creating his own empire modelled on his twisted views of humanity. More specifically, a world without addictive drugs, guns and nuclear and chemical weapons.
Though to note, there are many points in the story that explore Tsukasa's psychotic behaviour. One instance is when he first breaks a stone statue and has no remorse, continuing to crush more in his wake. He particularly goes after older adults and elderly people, but specifically leaves children alone. This can be related to his personal background and history of being assaulted and abused by those in authority. He also ends up taking Yuzuriha hostage in order to gain the Revival Formula. Tsukasa also by no means wants to resort to fighting or killing, but will do so if he feels pressured or his vision for humanity is at stake. This is seen when he ended up killing Senku after sharing a tender moment of wishing they could've met 3,700 years earlier.
Tsukasa is a highly intellectual individual. Tsukasa also states that Senku is the only man he has met who is smarter than him by massive inquiring levels. From this, it's assumed that Tsukasa has spent most of his life alienated from social customs because of his prime intelligence (feeling that no one would understand him) and current predicament with his clinically brain dead sister, Mirai.
Physical Abilities: Edit
True to his epithet, Tsukasa possesses an extreme amount of strength. He was able to kill the leader of a pride of lions with a single punch, scaring the rest of the pride off. He also managed to cut down a tree with a single strike from his stone sword, a tree which Senku noted to weigh 1 ton.
Tsukasa's speed and reflexes are equally extreme. When Senku shot a crossbow bolt at Tsukasa, he simply caught the bolt with his bare hand, with Senku later noting that the bolts moved at 200 km/h. He was also able to easily parry all of Kohaku's swift attacks during their quick scuffle.
In addition to his enormous strength, speed, and reflexes, Tsukasa is also a tremendously skilled fighter, as he had dominated the UFC while only in high school, and remained undefeated. Tsukasa's fighting style appears to be similar to Muay Thai (kickboxing) demonstrating techniques, such as the Flying Knee, Roundhouse Kick, but also spinning back Kicks from Taekwondo. As a mixed martial artist, it could be inferred that he had mastered many forms of martial arts.
- After being freed from his petrification, Tsukasa began wielding a primitive-looking spear with a stone blade to hunt for fish.