Light Novel Volume 17/Synopsis

Prologue: The Coronation
In the aftermath of the Takt, the false Hero's, invasion of Melromarc, the world started to rebuild. Faubrey and Shieldfreeden who backed Takt are now paying for repairs and the defend the waves. After Queen Mirellia Melromarc's death, Trash conducts Melty's coronation as the popular new queen. After the ceremony, Naofumi's party congratulates Melty. Naofumi teases her about her new responsibility so Melty retaliates makes him an archduke to his dismay. Upon hearing this, Trash proudly approves and reminds them that as an archduke, the two of them are technically engaged. Both Naofumi and Melty try to refuse but their pleas land on deaf ears and their engagement remains

Chapter One: Talk of Love
Naofumi heads back to his village after the coronation ceremony and on the way he meets Ren and Eclair. Naofumi and Ren discuss what they want to do when they defeat the waves. Ren hasn't decided whether he wants to stay or go back to his world since he's now made relationships that he values deeply - including Eclair. However, Eclair seems oblivious to his affections and doesn't seem to be ready for a romantic relationship. Naofumi encourages Ren while Ren and Eclair teleport to the Melromarc's castle.

Chapter Two: Limit Break
Heading further into the village, Naofumi meets up with Ethnobalt who had recently crossed over from his world. According to Ethnobalt, they have three days before they can cross over again. Naofumi plans to take advantage of this time to level up and prepare. The first thing on his agenda is to use Gaelion's new knowledge as Dragon Emperor to break the level-100 limit for their party. Everyone who was ready got the level breaking ceremony including Sadeena, Shildina, Raph-chan, and Raph-chan II. After the ceremony, Naofumi went training in the ocean with Sadeena, Shildina, Ruft, Raph-chan II, and Ethnobalt. Sadeena and Shildina both test out their massively improved abilities and Ruft reaches the level 40 limit. Back on land, Ruft receives a special class-up from Raph-chan and is sent to learn leadership with Melty. Using the experience-rich seabed, Naofumi and Ethnobalt train the remaining 3 days until Ethnobalt reaches about level 100 and Naofumi reaches level 150. Finally, Naofumi heads over to Erhard's shop to upgrade his equipment to be compatible with Ethnobalt's world.

Chapter Three: Party Selection
The day before Naofumi leaves to Ethnobalt's world, he and the other Legendary Heroes meet up and discuss who should be on the rescue party. According to the shield, he can bring multiple people along but are limited by the number of legendary heroes. Filo and Rishia were selected since they previously went to that world and their levels would only be reset to what they were over there. Itsuki, S'yne, and Raph-chan volunteer and are accepted into the party. Sadeena is allowed to come while her sister was eventually convinced to stay to protect the village. The rest plan to stay at the village.

The next morning, the party prepare to head out. When everyone was ready, Ethnobalt used his accessory to travel to his own world.

Chapter Four: Arrival into Conflict
Upon reaching Ethnobalt's world, Naofumi discovers that Shildina was accidentally caught up with them during the transit. As expected with moving to a different world, everyone who hasn't been to Ethnobalt's world was reset to level 1. As an unexpected result, Shildina transformed to a child. Looking at their surroundings, they had arrived in an empty, burned down town near L'Arc's castle. Traveling to the castle, Naofumi's party finds the area in chaos. Raphtalia and L'Arc's party were being driven back by an unknown enemy force which had stolen L'Arc's Vassal Scythe. Driven in a corner, Glass prepares to use the curse series of her Vassal Fan. Naofumi stops her and casts his most powerful buff spell on his allies. With their new strength and backup, the enemy is quickly defeated and the Vassal Scythe is returned to L'Arc. Raph-chan destroys the soul of the leader of the enemy to prevent him from reincarnating.

With most of the remaining enemy retreating, Naofumi finally reunites with Raphtalia. He updates Raphtalia and this world's heroes on what happened with Takt's invasion. After the joyful reunion, Naofumi introduces the new people from his world and L'Arc updates them on the latest events. Apparently, another tyrant similar to Kyo had just tried to invade L'Arc's country. Kizuna also tried to summon the other Legendary Heroes for help but they refused since they believed that they were in a video game. They were eventually killed by a group of Vassal Weapon holders which had made the waves worse. Kizuna was the only one left but was recently captured. After recovering from the recent battle, Naofumi and L'Arc's parties decide to rescue Kizuna together.

Chapter Five: Inter-World Adaptation
Preparing to save Kizuna, the members of Naofumi's party who were reset to level 1 were given earth crystals to level up. In the meantime, Naofumi and the heroes from this world went to meet Romina the blacksmith. Naofumi asks her to tweak his current Barbarian Armor to be fully compatible for this world. He also returned the Demon Dragon core which had previously possessed Gaelion. Finally, he requested weapons for the rest of their party since some of their equipment stopped working after changing worlds. On the side, Romina mentions that L'Arc is jealous of Naofumi and Therese's respect for his accessory crafting.

Chapter Six: Hidden Abilities
Returning to L'Arc and his party members, he found that Sadeena and Shildina have significantly leveled up and are now training with L'Arc. Eventually, L'Arc is challenged to a drinking contest with the two killer whale sisters and he agrees to try to make Naofumi feel jealous. Therese tries to get him to back down but he insists on the competition. After everyone eats a meal that Naofumi had prepared, the three start the contest. L'Arc almost immediately gets drunk and collapses.

After the meal, while Naofumi is talking to Glass about the worsening waves, Itsuki starts to play music with the band. He shows extreme talent for an instrument that he hadn't played before and even starts to conjure magic with his music. Naofumi then talks to Shildina and Glass and discovers that spirit people are innately afraid of Shildina due to her oracle powers. Afterwards, Glass and those in Naofumi's party with a sufficient level went out to look for Kizuna.

Chapter Seven: Finding Kizuna
Information to be added later on.

Chapter Eight: Subterranean Maze City
Information to be added later on.

Chapter Nine: Outsider Theory
Information to be added later on.

Chapter Ten: A Familiar Face
Information to be added later on.

Chapter Eleven: The Mirror Vassal Weapon
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Chapter Twelve: A Falling Out
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Chapter Thirteen: Forced Possession
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Chapter Fourteen: Quick Adaptation
Information to be added later on.

Chapter Fifteen: Mirror
Information to be added later on.

Epilogue: A Responsibility to Justice
Information to be added later on.