Suika (スイカ) is a descendant of modern humans and an inhabitant of Ishigami Village. She's one of the main protagonists of Dr. Stone.
Having initially been ostracized for her clumsiness and constant usage of a watermelon helmet due to her nearsightedness, she quickly makes friends with Senku who doesn't judge her immediately by her appearance and later helps her regain normal sight through lens.
She's a caring, inquisitive individual with a talent for spying. She seems to be a little shy, mostly because people saw her as weird for wearing a watermelon over her head (revealed to be because she has bad eyesight, and looking through the watermelon allows her to see a little better due to the pinhole effect). She's become one of Senku's closest allies ever since. She's moved when Senku doesn't ask her about the watermelon she wears or calls her weird for wearing it (though it was most likely because he doesn't care).
However, once Senku makes glass lens for her using the watermelon head, she's grateful for him fixing her eyesight, and declines to get more, "normal practical", glasses, opting to keep her watermelon head. She's shown to be brave, as she purposely leads the Tsukasa Empire troops away from the village by using herself as bait. She also enjoys helping Senku and her friends. For example, when Senku needs volunteers to spin thread, she immediately volunteers herself and the other kids, stating that she would prove they could be useful.
As a kid, she's curious and enjoys exploring. Also, she occasionally doesn't understand some of the more, "adult", topics discussed, such as wondering what the village sisters mean when they say boyfriend or wondering what a harem is. Nonetheless, she has proven to be intelligent as she managed to understand Gen's path and his message based on some flowers he left behind. Similarly, she is observant enough to understand that Kinro has the same bad eyesight problem she has after she watched him fight for only a few minutes.
Possibly due to her lonely childhood being ostracized for wearing a watermelon helmet and lack of coordination due to her nearsightedness, she's quick to make friends and she's very friendly and kind. She immediately becomes friends with Mirai and states how happy she is to have a female friend her age. She also wants to be of help to others and dislikes it when she can't help others.
She seems to have a fond of animals, like having a pet dog named Chalk, and she bonds with a pig that Francois planned to use as an entree, to which Senku and Francois relented and allowed her to keep it as a pet, much to her joy.
Suika's a young girl of short stature with blonde hair in a bowl cut being described as cute by many of the other characters.She has to wear a helmet made from a melon rind to help her see better because she has a disease called "blurry sickness" or in modern terms: nearsightedness. Senku created a pair of glass lens in her helmet to help her eyesight. She wears a black dress that covers her whole body, and she has a rope attached to her neck like a necklace, and it's common for her tribe to wear them most, especially for girls.
Since Suika had the blurry eye disease (nearsightedness), she constantly scrunched up her face in an attempt to see things. This ended up scaring people, so she started to wear her trademark melon helmet.
She makes her first appearance emerging from a river and offering to help Senku collect iron. She is very grateful for Senku not mentioning the reason she wears her signature melon helmet and being nice to her. Having collected enough iron sand, Suika assists in trying to melt it along with the group, albeit to no avail. As Senku explains that in order to get more villagers on his side, he will need intel on their likes and personality. Suika volunteers to spy on them in order to gather information, hiding herself in the melon helmet, much to everyone's surprise.
Suika begins her surveillance over the village and oversees that most of the villagers are suspecting the leader is trying not to escalate the situation since Senku has so far stayed in Chrome's warehouse. Suika then snuck around and was asking villagers if there is anything they currently want or need. She informs Senku that Garnet, Sapphire and Ruby want boyfriends, something that cannot be achieved by Senku's science. Suika then mentions that the village's glutton, Ganet, wants a new type of food, as he is sick of eating grilled fish constantly. Happy that he found his inner man, Senku elaborates that through science, they will make a delicacy for the villagers. Together, they filter out the the green foxtail and grind it with different ingredients to make ramen. The villagers notice the enticing smell, as Senku reveals his plan of alluring the villagers to his side through bribe with food.
With the introduction of Gen Asagiri, once he mentions scaling whether to join Senku or Tsukasa while also noting that with Tsukasa he could have a harem, Suika asks Gen what harem means. A flustered Gen tells her she's better off not yet knowing.
Confused, Suika wonders whether Gen is a bad guy due to being sided with Tsukasa. Senku responds with saying Gen is neither a good nor a bad guy, while Kohaku calls him a pure opportunist. The former tells the group they need to incorporate him into Kingdom of Science anyway, since they need him to lie to Tsukasa about Senku's status.
Suika comes rushing to Chrome's cottage with news. She lets Senku, Kohaku and Chrome know that it was Magma who planned to eliminate "the sorcerer" of the village and instead attacked Gen. The group figures out that Magma probably thought Gen was the sorcerer as he showed the villagers the flower trick. She also tells them Magma planned to kill Kohaku although she left no openings for him to do so. Magma concludes that Kohaku isn't much of a threat without the sorcerer with her, and says he could take her in to become his woman if she begs for mercy.
Along the way, Senku says the group will need glass in order to concoct an antibiotic for Ruri. He then suddenly pulls Suika's helmet of, claiming she won't need it anymore once they find adequate glass for her. Everyone is surprised by how cute Suika is, only for her to make painful grimaces quickly after her helmet is removed. She claims her eyes have the "blurry disease" - she is only able to see blurry images and is ashamed of her constant grimacing in order to see better, however her vision gets improved once she puts her helmet with two holes on. Senku explains that this is a pinhole effect - focusing the amount of light on an iris to make the image sharper. He then goes on to explain science can make her see well.
Suika being fascinated with that the advanced civilization could do, emotionally states that she wants to see people around her clearly for the first time in her life. Willing to aid Senku in his endeavor. Once the lens are complete, Senku fits them into Suika's helmet, Suika being able to see normally for the first time in her life. She cries in happiness and tells Senku and Chrome they look a lot cooler than she thought, with a frustrated Chrome asking what exactly her expectations were and a devious Senku celebrating a new worker in the "labor force".
Suika is present when Chrome and Senku provoke Kaseki into helping them mold glass. The group eventually finishes the science lab.
When Senku makes a supplement drink for his warriors in the village tournament, Suika offers to help gather more as Ginro drinks the entire stock. She is then tied up by Mantle who claims to the group that she is drowning in the river, having accidentally fallen when collecting herbs for the drink.
Suika successfully frees herself of Mantle's ropes and arrives to the village fight. She notices Kinro's grimaces during the fight with Magma as the latter makes distance between them and so gives her mask to Kinro in order for him to be able to see better, but in the end, he gets beaten. As Kohaku almost arrives to the village, Magma orders his lackey to surrender so that the next match automatically puts Kohaku out of the competition as she isn't present. Suika fervently apologizes to Kohaku for being captured by Mantle, only to be hugged by the latter who says that all she cares about is that Mantle was lying and Suika is well.
Once the match between Ginro and Argo is over, Suika comments on Ginro's fainted state. Eventually, as Chrome engages Magma, Suika prays for Chrome's persistent training to pay off. With Chrome being overwhelmed by Magma's hits, Suika cries seeing how Chrome is desperately trying to protect her helmet from breaking more than it already has. Senku then uses the mask as a fulcrum for his stick and with it, he beats Ginro during the Village Games.
Once Ruri's condition worsens after taking the sulfa drug, Suika runs to warn the Kingdom of Science of the predicament. As Kokuyo gets mistrusting of the drug, Kohaku blocks his attack on Senku and states she believes in science and in Senku as well. Suika, along with the rest, agrees with Kohaku, prompting Kokuyo to release Senku and let him treat Ruri.
At Senku's orders, she delivers a small blade to Gen for him to sabotage Hyoga's spear. She then allows herself to serve as a distraction to save her fellow children from Hyoga's men. She leads them to the hydro acid fields. Suika is saved by Kohaku and Senku, who takes credit for creating the gas to intimidate the enemy. She returns with them to the village where Kokuyo congratulates her while Kaseki scolds her recklessness. 
Once the cotton candy machine is crafted as a part of the cellphone making process, Suika enjoys the taste of the sweet along with the rest of the villagers. She is later seen when Senku creates the record player and plays the record his father left, being amazed to hear the village founder. Suika finds herself in awe at Lillian's song, finding it beautiful.
Suika is scared to see Homura and is shocked by her knowing the names of everyone in the village. Kaseki tells her it was because she was spying on them.
When Ryusui invents his own currency, she opens up a ramen shop.
She and Sagara find the oil fields. Suika begs Francois and Senku to spare Sagara and they slyly allow her to keep the hog as a pet, to her joy.
Suika stowed on the Perseus but was discovered in the mid journey. Suika has to do work to earn her keep on the trip.
She hides out, as Ibara and his group search the ship. She distracts them and catches sight of Ginro (who also survived the attack), recalling she heard Kohaku shouting for the lab. She distracted the enemy long enough for him to help her retrieve the mobile lab and meet up with their allies. 
She helps in the creation of the oxygen tanks after several hours they are complete. Despite the concerns about the few minutes, Soyuz and Ryusui have to save their friends they are ultimately successful.
Later on, she is ecstatic to see Ryusui revived and is congratulated by him with him declaring her to be an true warrior for the kingdom of science. She assists in the reconstruction of the statue of the great leader only to be petrified along with everyone else except Senku when Ibara petrifies the entire island.
Suika is shocked about the Whyman, wondering if this meant he was really Senku but Chrome points out to her that the real Senku was with them. She later witnesses the revival of an unknown man who tells them of other weapons that once fell from the sky. 
She helps her allies with reviving others on the island, aiding the children who were petrified by reviving them. She later departs with the others back to the main land.
After establishing that the Whyman is on the moon and that the crew of the Perseus needs to travel around the world to collect items to build a space shuttle, Suika is allowed to come along as a reward for her help during the treasure Island arc.
Once on the Perseus she witness Senku and Ryusui's poker match, being on team Ryusui, despite not knowing much about what is going on.
After the poker match and witnessing Francois mix a cocktail for her, Suika becomes worried due to the cocktail possibly containing alcohol, however, Francios reassures her that it is a non-alcoholic cocktail, made to taste like a caplico soft drink. She becomes delighted by the personal drink that is made for her.
Suika continues the celebration and watches Matsukaze faint after one sip from his drink. She is happy when he wakes up.
She later gives Chrome the idea of finding of gem capable of detecting the sun like in the days of Vikings and assists him in locating it. Once the Perseus enters the waters closer to America, she along with other stone world members of the crew becomes amazed by creatures such as whales and structures like icebergs. After the Perseus reaches America she is she celebrating on the edge of the ship, along with the rest of the crew.
Once on the shore she is part of the team responsible for scouting out corn and enjoys a burger for the first time after Francois successful cooks the alligators that the power team defeated. 
She is later shocked to hear that she was chosen as part of a exhibition team in combating Dr. Xeno alongside Hyoga, Tsukasa and Ukyo. 
Abilities and Equipment
Suika is trusted by Senku and his friends to let her go on scouting. She is able to roll herself inside the melon hat, allowing her to recon deep into enemy territory undetected. Suika is able to slip past through hostile units when she attempts to retrieve the mobile lab from Perseus after the whole crew, with the exception of her and Ginro, are petrified by an unknown opponent. She is highly dependable when it comes to scouting.
Knowledge of Forests and Animals
She is stated by Francois to be the foremost expert of the forests and animals surrounding Ishigami Village.
She is shown to be intelligent and observant, quickly deducing Kinro was losing the fight against Magma because he is nearsighted like her and he couldn't judge the proper distance to attack him.
Since getting her glasses, Suika has shown that she's able to be quite quick, which comes in very handy for stealth and especially for outsmarting enemies, as shown when she confronted Tsukasa's soldiers. While not as fast as other characters, she has shown to be speedy enough to get back from being tied up by Mantle to witness the match between Kinro and Magma. She was also speedy enough to outrun adults such as Tsukasa's soldiers, Hyoga, and Homura. Her speed ability proved invaluable when it came to rescuing the science lab from the ship after it was overrun by the Petrification Kingdom.
- Her name Suika is the Japanese word for Watermelon.
- This comes from the watermelon she wears over her head, which comes from a plant of the species Citrullus lanatus, bearing a melon-like fruit.
- She is one of the most popular characters in the series, ranking in the top ten in every popularity poll she is in.
- Suika tends to refer to herself in the third person in the manga.
- Suika has yet to grow too big for her melon helmet, but he she does so, her stealth ability will go down.
|Male||Taiju Oki • Senku Ishigami • Gen Asagiri • Chrome • Kaseki • Kinro • Ginro • Magma • Kokuyo • Ryusui Nanami • Matsukaze • Tsukasa Shishio • Hyoga • Mozu|
|Female||Yuzuriha Ogawa • Ruri • Kohaku • Suika • Nikki Hanada • Minami Hokutozai • Kirisame • Homura Momiji|
|Male||Chrome • Ginro • Jasper • Kaseki • Kokuyo • Kinro • Magma • Mantle • Soyuz • Tetsuken • Ibara • Mozu • Oarashi • Matsukaze|
|Female||Garnet • Kohaku • Ruby • Ruri • Sapphire • Suika • Shirogane • Shovel • Turquoise • Amaryllis • Kirisame|