|Class and Year||1-F|
|Physical and Vital Statistics|
|Manga||Volume 1 Chapter 1|
During the cruise, he acquires his precognitive abilities from a girl named Sakura who plays a chess-like game with him. He becomes a loner but eventually opens up to his classmates. He lives in the Quest Dorm with many beautiful girls and one guy who looks like a girl (Megumu). Later he discovers he is a Bladefield family member, Nanami's younger brother and Hakua's older brother, thus revealing his real name to be Souta Bladefield.
Souta is a serious teenage boy who often tends to play the straight man in a majority of his friends' crazy antics.
Despite this, he does have a kind side as he helped Serika Ginyuuin overcome her fear of a possible failure at her concert and attempted to save Akane Mahougasawa from a fall and saved her by changing her flag. Indeed, his kind side has earned him the affections of several girls even girls like Akane, Mimori and Mei. Even girls such as Serika and Rin who were once hostile to him at first have changed their opinion and come to like him because he was somehow connected to their past. As he is perceptive, Souta is aware of the girls' affections for him and blushes when they have a moment while he is annoyed or put off by their change in behavior becoming too much for him to handle.
He initially tried to avoid making friends with others, as he doesn't want anyone to be hurt because of their affiliation with him. However, this had changed following his friendships with the girls of his dorm who have gotten him to open up a little more.
Due to the trauma he experienced in a ship submergence accident, he is very scared around water and tend to freeze up whenever he has to go near it until getting motivation to approach it.
In spite of being a rational character, he likes making jokes though he does so with a serious face.
He has the ability to visualize "flags" for future events and helps people with that ability. As seen where he saved Nanami from a truck and saved many people from being hit by a truck by dejecting their spirits. After being confronted by Nanami Knight Bladefield, he explained his ability to see flags and ended up befriending another girl named Akane whose friendship flag kept returning after breaking. He later saved Akane from dying when she fell down stairs by kissing her, which led to her developing feelings for him. He got these powers in a game of chess against a young girl named Sakura, they had agreed that the loser would have to obey the request of the winner. After Souta lost and got these powers she said that in return he must arrive at the truth of this world and after he arrives at the truth of this world she will come again and they will battle again.One day, he gets a strange letter which tells him to find princess, knight, magician, clergy and the shinobi and that the sword and magic will raise the first flag. After that the flag raises above his head. After he gave up hope of breaking the flag and didn't know what do anymore he realised that maybe the princess, knight, magician, clergy and shinobi were the girls from the dorm. After that Ruri started acting weird she asked if Souta wanted to go to the other side of the world. She then said 'The first door that is opened by four heroes hoist the king's flag. It is connected to the other side of the world, where people who can tear away the darkness within the king's flag awaits.' Souta reaches the conclusion that if he goes to the other side of the world he can cancel the dark flag, so that's why someone asked to find the princess, knight, magician, clergy and shinobi and when he asked if Sakura was connected to this Ruri said that he needed a code to know that, he is then shown a project hologram by Ruri.
Souta saw Nanami as the knight, Akane as the magician and Ruri as the shinobi and an unknown person as the clergy. Nanami told him that he was the kings flag and then they opened the first door. There they saw a part of Souta's past. Souta was there with Sakura and after Sakura said that if he can arrive at the secret of this world the ship he was in was suddenly engulfed by flames. He was desperate to escape and he didn't have time to think about Sakura. When he was escaping he saw for the first time the dead flags on peoples heads and the only one who didn't have a death flag was Souta himself and then the hologram stopped.
After that he thinks that the keys to open the doors are gathered at the quest dormitory, so he needs to win the sport festival because otherwise the dorm will close down and in order to win he needs to raise the flags on everyone's head and he needs the help of Ruri to do that.
During training, he meets a strict girl named Rin Eiyuuzaki who is sent to ensure their victory. In a talk, he learns that she had a friend who treated her equally and she said he was a really good person. She regarded him as her best friend although she hasn't seen him for a while they are still exchanging mails. Souta said that he also knew a person named Rin, but the Rin he knew was a boy and he also called him Soda. After that Rin said that she would send a mail to Soda and when she sent the mail, Souta's cellphone rang and the message she sent was on his phone, making it clear to them that the friend she was talking about was Souta from the start and the boy Rin that Souta was talking about was actually Rin who wore a hat over her long hair as a child.
The two realized the other's identity, which freaked out both of them who questioned the supposed change in the other's attitude and appearance until Rin nearly fell and Souta quickly saved her. After seeing that he was still the Souta she knew, Rin broke down and repeatedly apologized to him for her current behavior towards him, as this happens Souta spot a yandere flag on her head. Not knowing any other way, he tells her that their friendship won't be tarnished because of such a thing when she asks if that's true he affirms that it won't. Rin's flag breaks as she realizes he is right and Souta is confused by her girly nature compared to when they were children.
After processing this, Souta has her call him by his real name since he is embarrassed by her nickname.
On the day of the Sport festival, he acted really nice to everyone to raise the victory-flags on everyone's head. During the last event they sadly lost, but the higher-ups said that they had enough points to earn second place and that is enough to win the mvp.A couple days later after the festival and after they went to the beach. Souta talks with Mei about her powers. Mei’s powers are limited, while Souta apparently has the power to change the fate of the entire world. This is because Souta’s powers were given to him directly by the “Sacrament” herself or rather, Sakura, the girl he met on the cruise ship.Mei is a member of the Council Seven, who are tasked with maintaining the order of the world. She is also tasked with watching over Souta so he doesn’t throw the world out of balance with his powers. Summer vacation is almost over and before they were about to go back to Japan. Souta is greeted by Zero, the leader of the Council Seven. She tells him a tale of a boy who sacrificed his life to save two princesses, and became a flag. Souta realizes right away that the tale is suspiciously similar to the events of his own life, and is thrown into a deep despair. Zero leaves him to muse about what she’s told him.
The festival is starting and Souta and Nanami ran into a stange girl and later on find out that she is the idol Serika. It is revealed Souta helped her in the past when she was crying and told her she had a success flag but she didn't know his identity and calls him the "Purple Flagman" due to his wearing a purple hoodie. Nanami interrogates him on this as he reveals on that that day he was trying to kill himself, but when he saw Serika he wanted to do something good before ending his life and after helping her he couldn't kill himself anymore.
On the final day of the festival, he realizes that Serika is the bard. During the concert, Souta's power increases once more, and the time freezes up. No. 0 appears and tells Souta that he should not be in the world, or the world will be destroyed. So, despite Souta had promised the Quest Dorm members to dance with them, he breaks the promises and uses his power to make everyone forgets about him. Nanami, unaffected by Souta's power, is the only person who is able to remember Souta.
In the servers, Souta desperately fights the Angelus Gemini in order to protect his world and his friends by placing "Death Flag" upon his enemies. When Souta was really tired from the battling, the Quest Dorm members came and saved him.The girls fight the Angelus Gemini, while Souta wonders why they came, feeling he has nothing to give them in return. Akane assures him that's not true, and eventually proffeses her love for him before she goes to fight. The Premium Ambriel absorbs the remaining creatures to charge a final attack, while Souta regains memory of his past as he tries to stop the attack. It is revealed that he once knew Akane, Kikuno, Megumi, Rin and Nanami at one point, but due to an accident, Souta chose to have a little girl, known as Laplace's Demon take their death flags and have them formed on him so they would survive. The price being the girls were to lose their memories of the event, and Souta and the girls were to forget having ever met each other while Souta despaired his life. Back in the present, Souta then uses his full power against the Premium Ambriel, and while his strength alone is not enough, he manages to destroy it with the help of the other girls coming and aiding him. During this time his death flag breaks. Souta then wakes up in the real world, where Number 0 speaks to him about the state of things and the truth about Sakura and Laplace's Demon. She also says that he was in an accident before he enrolled at a school, so she merged his conscious with many virtual worlds. Before she leaves, she states that the time he spent in the virtual world was but a flash in reality, hence nobody else shares his memories of it, including Nanami who dived into the virtual world to save him.
Later, Souta goes to Quest Dorm and finds Akane there but he is sad that she doesn't remember him. However, he recalls a spot upstairs with a bad step and rushes there managing to save her from falling through the floor once more. Akane thanks him as he saved her like last time, revealing she remembers him again. This surprises him but relieves him as they embrace each other.
Later on Christmas, Souta spends time with his friends and despite several embarrassing situations he ends up enjoying himself. He then personally spends time with everyone with crazy results especially with Akane who makes her lap a pillow for his head. When he meets with Serika, she is hostile to him before she finds out that he is the Purple Flagman after discovering his hoodie and him accidentally confirming it to her. Serika changed her view of Souta and developed feelings for him, as shown when she blushes and profusely apologizes to him for her treatment to him and now calls him "Hatate-Sama" since it was him who helped her out. Serika calmed down and says she hoped to meet him again and wished that he wasn't angry but after noticing Souta stutter when he said he wasn't mad, she became flustered again and even offered to hurt herself even when he tells her its alright before Nanami drags him out of the room.
At the end, while spending his time with Nanami, the other girls (and Megumu) fall out the doorway after eavesdropping on them with various reasons. He shrugs this off and helps them up while wishing them a merry Christmas, causing a majority of them to blush. They all wish him a merry Christmas as they return inside the dorm.