Sadeena/Chronology

Volume 4
When Raphtalia found Keel in Idol's dungeon, she proved her identity by reminincsing about when Sadeena saved Keel from drowning.

Volume 5
Just before the wave at Cal Mira Island, Raphtalia wishes that Sadeena was there to fight in the wave. She was revealed to be the best swimmer in Lurolona Village and was like a sister to Raphtalia. Naofumi admits that a swimming-type demi-human would be very useful when fighting in the water.

Volume 10
As Naofumi was setting up food supplies for his village, Raphtalia wishes that Sadeena was present since she a fisher and a strong fighter. She was unable to protect the village from the waves since she was deep out at sea fishing at the time.

When Naofumi and his party went to Zeltoble to free slaves that had come from Raphtalia's village, he had unknowingly met Sadeena under the stage name "Nadia." Nadia had proved to be friendly and very knowledgeable about the coliseum but was also a bit of a drunkard. As she explained the workings on the coliseum, she kept on ordering drinks for the both of them. When Naofumi learned enough for the day, he paid for the drinks and left.

After Naofumi started participating in the coliseum tournaments, the two met met again at the tavern. As before, Nadia provided advice over drinks. As they talk, Naofumi reveals that he can't get drunk which thoroughly impresses her. Nadia then takes him outside as they continue to talk until they are both ambushed by some opponent fighters. Nadia shows off her impressive combat skills as she defeats them and then warns Naofumi about further ambushes. She then professes her love for Naofumi and heavily flirts with him as she reveals that she tried to poison Naofumi with extremely potent alcohol. Naofumi immediately rejects her and she then heads out, hoping that they will meet again.

A few days later, as Naofumi, Raphtalia and Filo advance up the coliseum, they were finally scheduled to fight against Nadia. Before the fight begins, Nadia reveals that she knows that Naofumi plans to buy all of the slaves from Lurolona Village. With Naofumi's team under the effects of a curse that significantly reduces their stats, Nadia shows extreme skill in close-quarters combat, magic and tactical maneuvers. In addition, supporters in the stands paid to enhance Nadia and debuff Naofumi's team. As Naofumi's team gets knocked around by Nadia, she eventually turns into her therianthrope form. Raphtalia recognizes her and calls her by her real name - Sadeena. As they pretend fight for the spectators, Raphtalia brings Sadeena up to speed on their mission to rebuild the village. Apparently, Sadeena has also been working to buy back the villagers. After making a flashy performance, Sadeena pretends to be defeated.

At the disappointment of the coliseum spectators, Naofumi's team and Sadeena are matched up against the final opponent of the coliseum - Murder Pierrot. During the difficult fight Sadeena showed Naofumi how to cast cooperative magic together. With that magic, they were able to defeat Murder Pierrot. After the battle, they confronted the crooked merchant running the coliseum. Sadeena's debts were waived and they returned to Lurolona village with the missing villagers. Back at the village, Raphtalia and Sadeena reveal why Sadeena has been overly flirtatious with Naofumi. Apparently she's always wanted a partner who could drink more than her and Naofumi is the only person able to do it.

Volume 11
Back at Zeltoble, Sadeena goes with Naofumi to the slave traders. While there, Sadeena recognizes and points out Fohl from the coliseum. Naofumi decides to buy both Fohl and his sister Atla.

Back at the village, Sadeena worked on helping the villagers level up and protected the village from any attacks. Naofumi starts to become intimidated by Sadeena's advances. Eventually, he decides to have Sadeena reset her levels so that he can optimize her build to which she easily agrees. After the level reset, she starts leveling up in the ocean.

Later on, Sadeena successfully teaches Keel how to transform into her therianthrope form.

Volume 12
Information to be added later on.

Volume 13
Information to be added later on.

Volume 14
Information to be added later on.

Volume 15
Information to be added later on.

Volume 16
Information to be added later on.

Volume 17
Information to be added later on.