Saltherine Aldarake

Saltorine Aldike (known to everyone as Sari) is the protagonist of Peach Boy Riverside. We are introduced to her as a princess who dreams to go out and see the world. After meeting Mikoto and watching him slay a hoard of Oni, she decides to start an adventure of her own.

Personality
Sari is a kind-hearted spirit who craves adventure. She is always protective of her friends and longs to fulfill her goal of having humans and Oni live together in peace.

Chapter 1
Sari is introduced in the series as she is running away from her father's guards in the hopes of exploring outside of the castle. She is dedicated to going on an adventure and seeing what lies beyond. She runs into Mikoto and asks him to lie to the guards about her whereabouts, to which he agrees. The guards leave, and Sari introduces herself to her new friend. She then invites Mikoto back to the castle for free food and shelter. The next day, Sari expresses shock as she finds out that Mikoto is a boy. As they wonder the castle grounds, Mikoto tells Sari of his journeys. Sari jokingly comments since someone as weak as Mikoto can travel about, she should be able to as well. She asks him to take her with him. Mikoto changes his tone, and tells her his path is very dangerous; he might abandon her, or she might lose her life. He then asks that if she knows this, would she still join him? Sari is taken aback, to which Mikoto says he was joking.

Inside the castle, Sari's father the King meets with a stranger who reveals himself to be an Oni. He tells the king he will require at least thirty bodies a month as payment for tribute. A knight tells the Oni to back off and before the knight can finish, he is beheaded, to which the Oni states this sacrifice does not count. The Oni leaves the King's presence and sees Mikoto in the courtyard. He begins to worry as his plan may not work out as planned. Cutting off Sari's conversation, Mikoto senses the Oni and pursues him without Sari realizing. Inside the castle, there is a great commotion around the King as to how they should confront this newfound threat. The King approaches Sari and tells his daughter that she should go out and start her own journey, knowing full well it would be too dangerous if she stayed. Suddenly a rumbling is heard outside and Sari rushes to see what it is. Seeing Oni for the first time, she determines she must get closer.

Out in the field, the hoard of Oni gather and meet the Oni who spoke to the king, Yaki. Yaki tells the leader of the hoard, Mouki, that the plan is off. Mouki touts that he is there in the field as a result of losing his homeland. Yaki screams at him that the person who destroyed Mouki's home is there in the castle. Mikoto approaches the hoard, to which Mouki gets excited at the prospect of strangling him. Sari shows up and screams to Mikoto that he has to leave right now. After an introduction between Mouki and Mikoto, the Former strikes first with a left punch; Mikoto cuts his hand off.

A narrative reveals that Mikoto is from oversees and that he kills Oni for pleasure. Mikoto slaughters the hoard with a noticeable bloodlust and at last approaches the bleeding Mouki. He asks Mikoto what he is, to which he responds that he is a helpless traveler who hunts Oni.

Back at the gate, Sari is conflicted that though Mikoto saved her kingdom, he did so in a terrifying way. A dog suddenly appears and Mikoto expresses that its time to leave. Sari begs Mikoto to stay and tell her more about travel and Oni, and tries to pursue him. She is stopped by the corpses of the Oni in her way and falls to her knees in disgust. Mikoto keeps walking forward but Sari calls out to him, only to realize he had been gone a month and she is still dreaming of him. Sari approaches her father and tells him that she is finally going on an adventure. Much to his surprise, she cuts of her long hair and joyfully tells him she is no longer going to live as a princess. The King asks her if she has a plan and she responds she'll go see the world first and then come up with a plan after. Sari is surprised at her father's support, and even more surprised he won't stop her. The King smiles and tells her to take care of herself.

Trivia

 * As of Volume 5, we have not seen Sari's father or heard if she has any other family