Maruki Takuto

The savior of mankind
Prior to the events of Persona 5, Maruki's fiancé's parents were murdered during a home invasion, and Rumi herself was injured in the process, leading to her falling into a catatonic depression. Maruki tried to comfort her, only to unwittingly invoke her trigger phrase by mentioning her family and driving her into a breakdown. In extreme grief, he unconsciously contacted a mysterious entity (Implied to be Adam Kadmon), and made a deal with it so as to allow him to harness its ability to manipulate cognition, dubbed Actualization. First applying this, he purges Rumi of her traumatic memories, but inadvertently also wipes her of any memory she shared with him and alters them to compensate for this. As to not remind Rumi of her grief, Maruki cut ties with her. While he was already researching cognitive psience by then, this further motivated his research so he could help humanity as a whole.

Initially, his research was met with positive reaction, but suddenly, his research was swiftly rejected by his university and funding was revoked under the pretense that there was a lack of evidence to support it, and his lifelong dream of opening a cognitive psience research center in place of a stadium in Odaiba was crushed. Unbeknownst to him at this point, his research was seized by Masayoshi Shido. Therefore, his dream never came to fruition and he left university as a result. This further motivates him to investigate deeper so he can validate that his own brand of work was true. Eventually, his research reveals that use of cognitive psience might be dangerous. While at first terrified, he continues to use his Actualization powers to assist people and make a better world.

Somewhere around this time, Maruki materializes his Palace in the Metaverse, although the period is never directly specified and the exact moment is not shown.

He opened a clinic, eventually using his power on a girl known as Sumire Yoshizawa, who lost her twin sister Kasumi and wished to live as her. Using his cognitive warping abilities, Maruki subconsciously made Sumire think that she's Kasumi, by her request.

Maruki later becomes the student counselor at Shujin Academy, and one of the protagonist's Confidants. Maruki is hired by Principal Kobayakawa in order to improve the students' mental health (and the school's reputation) after dealing with the exposure of the Kamoshida incident. When he is presented in the auditorium, he makes a clumsy speech before being pushed aside by Kobayakawa to end the assembly. After the speech, he tries to convince the protagonist, Ryuji and Ann to talk to him. While Ryuji doubts if he's actually trustworthy, he gains the trio's trust quickly when the protagonist realizes that he might be useful for the Phantom Thieves' activities.

Since then, he regularly meets up with members of the Phantom Thieves and has encountered all of them, save for Akechi. His goal is to collect information of the desires of students from Shujin in order to present an essay to his professor, who he was determined to prove to that his original research was true.

During a session, he regularly offers snacks to his guests as a way of making them comfortable.

Maruki will leave Shujin on November 18th, during which he gives a speech for the students to avoid pain and negativity and live strong. He then personally bids the protagonist farewell. Additionally, before he enrolled to Shujin in order to research the resident students, a glimpse of him can be seen after the party escapes into the real world after Ann's awakening. During the last meeting with him after his final speech in the Shujin auditorium, he will confirm that he witnessed the protagonist, Ann and Ryuji exiting Kamoshida's Palace.

The Slow Rumble
After receiving the title of Game Master from the previous owner Neku Sakuraba, Maruki started the second edition of the slow rumble with the help of a certain sponsor, with the objective to not only stop his arch enemy Joker from developing more people, but to also grant salvation to all of humanity.