Light Novel Volume 16/Synopsis

Prologue: The Funeral
A funeral is conducted for those who died in the battle of the Phoenix. Naofumi, Fohl, Raphtalia, and the rest of the village pay their respects to Atla who sacrificed her life to save everyone. Atla's death had inspired the rest of the village to fight in the waves. So far, there are no leads on who killed the Phoenix bird which then killed Atla. Queen Melromarc reports that the third Guardian Beast, the Kirin, was summoned hours after the Phoenix was killed and was promptly destroyed by some Seven Star Heroes.

Naofumi returned to the village, mentally unstable from Atla's death. Naofumi tried to comply with his promise to Atla to be open to other's attraction to him but in his mental condition, he overreached and made many awkward situations. Sadeena eventually pointed out his confused and misdirected think to set him straight.

Chapter One: The Ocean Floor
The next day, Naofumi declares that he's going to be serious about leveling up. Sadeena and Shildina offer to show their underwater hunting grounds. Before they head out, Melty gets Naofumi's approval to have a festival to celebrate the Phoenix's defeat. Fohl also gets tasked with finding out his Vassal Gauntlet's power-up methods.

As the underwater hunting group dives deeper, the monsters get harder and provide an excellent experience. In the next couple of days, they level up Naofumi while non-heroes like Sadeena reached the level cap at level 100. The second evening, the Old Man, Tolly, and their master came to the village from Q'ten Lo. They had finally purified the powerful cursed sword which was the Orochi's core. Unfortunately, it could only be used once before it gets cursed again. Ren copies it and Naofumi feeds the Orochi's core to Gaelion so he can gain more dragon emperor knowledge.

Chapter Two: The Festival
Three days later it was the day of the festival. At this point, Naofumi's village was the second-most important settlement in Melromarc, behind Castle Town. Filo opens up the festival with her popular singing. She is challenged by Motoyasu's main 3 filolials but as the contest escalates, the Raphs have the shut it down for everyone's safety. Naofumi looked around the festival and saw the whole village participating in running the different shops, stands, and events. Overall, the festival was a great success.

During the festival, the Raphs had done a ritual dance in front of the largest Sakura Lumina tree. The next day, a single large fruit had shown up which the Raphs passionately protected.

Chapter Three: The Genius
A week later, the large fruit drops and becomes a different type of Raph which Naofumi calls Raph-chan II. This Raph was born with a high level and was different from the rest of the Raphs. It then joins Naofumi's party.

By this point, Motoyasu made it to Faubrey, the location of all of the Seven Star Heroes, and has saved a teleport location there. The Heroes, the Queen, Trash, and some of Naofumi's party are selected as the diplomatic team to go over there. Naofumi suspects one of the Seven Star Heroes had killed Atla. The Queen gives a small tour of Faubrey and discusses its technology, history, religion, and king. She also talked about the Seven Star Whip Hero who was apparently a prodigy. With that, they enter the evil king's chambers.

Chapter Four: Stolen Power
To their surprise, the Whip Hero Takt was sitting on the throne. He boasts that he had killed the pig-king and had taken his place. He then proceeds to try to kill Queen Melromarc. Naofumi blocks and everyone realizes that this was the same attack that had killed the Phoenix and Atla. Suddenly, Naofumi's shield crumbles and then appears on Takt's arm. Apparently, Takt has the ability to steal Legendary and Vassal Weapons that he attacks. Takt's companions and Naofumi's party faces off but Takt's companions are much stronger. Takt mortally wounds Naofumi and the Queen while Malty arrives to praise him. Overwhelmed, Naofumi's group was forced to retreat. Raphtalia stays behind and allows the rest of the group to barely escape.

Chapter Five: The Spirits
Near-death, Naofumi and the queen are transported to the best medical facility in Melromarc. Unfortunately, the queen dies after treatment. Her last words were asking Trash to rise up and defeat Takt. Right after she died, news arrived the Faubrey had declared war on the entire world.

A couple of days later, Naofumi is still requiring intensive care. During the two days, Takt had started to attack countries with his new airplanes. Multiple countries have already fallen or surrendered. The heroes and leaders of Melromarc and Siltvelt have a strategy meeting. As Naofumi is near-death, he is suddenly met by Atla and Ost. His shield shows him visions of current events: Takt's invasions, Raphtalia's escape to Glass' World, and Raph-chan II placing an illusion on Takt's group. Finally, the shield offers Naofumi a chance to collect his reward for being a hero early. Naofumi could return back to his homeworld with 3 wishes, remain in Raphtalia's world, or go to his world with the option to travel back to Raphtalia's world. Naofumi decides to stay in Raphtalia's world.

Happy with Naofumi's decision, the shield answers Naofumi's questions through Atla and Ost. It talks about the nature of Heroes, weapons, and summoning. Then it gives all it knows about the 'World Eater' behind the waves. To defeat Takt, the other weapons allow Naofumi to temporarily use them. Naofumi gives a bittersweet goodbye to Atla and Ost and then wakes up.

Chapter Six: The Staff Hero
Waking up, Naofumi catches up on recent events with S'yne and then heads to the Queen's public funeral. At the funeral, Naofumi comforts Melty and gives his respects. However, seeing that Trash had given up on everything, Naofumi insults him and pretends to plan evil deeds. To fight Naofumi, Trash rises up and promises to protect Melromarc. With his passions burning and eyes cleared, Naofumi encourages him to be the wise king he used to be. Immediately, Trash's demeanor changed and his Vassal Staff accepted him again.

Naofumi and Trash join the defense conference. Trash's complete change and tactical abilities surprise the Heroes. They have a productive discussion on strategies to deal with Takt and his airplanes. Naofumi also unlocks the power-up methods for the Vassal Gauntlets and Vassal Staff. Upon the staff's request, Trash gives the Vassal Staff to Naofumi. After the productive strategy meeting, Naofumi brings Trash to his village to talk to Rat. Rat discusses Takt's alchemist and the Raph's abilities in battle. Trash then selected people from Naofumi's village to fight against Takt. Sadeena also brings in Larsazusa and Elmelo from the Zeltoble coliseum to fight against Takt.

Chapter Seven: The Wisest King of Wisdom
Melromarc is fully prepared to defend against Takt when he decides to attack a few days ahead of the predicted schedule. Trash believes that Takt has made every tactical blunder he could have made - he is just relying on his superior levels and technology. The Melromarc army then splits into two forces: Naofumi and his group attacking Takt directly while the rest of the force defends against the bulk of Takt's forces. Trash is easily able to come up with a strategy to defeat the airplanes and their high-level pilots.

Pretending to be messengers, Naofumi's forces sneak close to Takt and catch him and his harem by surprise. Naofumi takes on Takt directly while each of his party chooses their own opponent. With that, their individual battles begin.

Chapter Eight: X
Takt boasts in the number of vassal and legendary weapons he has. However, Naofumi deduces that he is unable to effectively use all of them at once and is just holding on to all of them because of his pride. Naofumi used the Vassal Staff's power-up method to improve his Aura support magic and cast the incredibly powerful spell All Liberation X. Now all his allies were buffed to near their opponent's stats and most seemed to be winning their fights.

Chapter Nine: Fenrir Force
Naofumi continues his fight with the upper hand against Takt. As Takt is losing, he is buffed by his teammates and uses Drifa-class magic but Naofumi is easily able to cancel it out. He accidentally kills the maid that S'yne was fighting which causes Takt to fall into a rage and reveal his naivety in battle. When members of Takt's harem see that he has been nearly defeated, they bring out 'Raphtalia.' Takt strikes at the illusion and kills the harem member that it was covering. Now that Raph-chan II wasn't creating the illusion of Raphtalia, she turns into Raphtalia's Ancestor and starts to fight against Takt's illusion specialist Tulina.

Takt finally realized that he killed one of his harem members and gets even more upset. Naofumi captures a group of his harem that has been interfering with their battle and holds them hostage. He redirects their attacks on him to torture Takt. Takt has been clearly defeated but Naofumi continues to attack for revenge.

Chapter Ten: Two Regular Guys and the Strongest Seven Star Hero
Desperately, Takt lunges at Naofumi who lets him take the Vassal Staff. Takt rejoices, believing that he has won the battle. Having defeated his opponent, Fohl joins Naofumi and the three continue the fight. Takt takes the Vassal Gauntlets but the two heroes continue to beat into him. The two hardly hold back enough to keep from killing him and the rest of their group finally defeat their opponents except for Raph-chan and Raphtalia's Ancestor who are still fighting against Tulina. Gaelion is able to devour the opposing dragon and gather knowledge through the gathered dragon emperor fragments.

Chapter Eleven: The Shield Hero Now Orders You
Surprisingly, Takt regains consciousness. However, Naofumi finally uses the authority as a true legendary hero to strip Takt of his Vassal Weapons and the Legendary Shield. The weapons then return to their rightful owners. Notably, Naofumi's shield saw a large stat increase since he was able to commune with the Spirit of the Shield and has Ost and Atla working to help him out. While Takt was stripped of his powers, Tulina was also finally defeated.

With Takt and his harem defeated, Naofumi signals to Trash that they were successful. Looking out, they were able to see that Trash defeated the Faubrey forces in battle. Gaelion starts to warn Naofumi about the Dragon Emperor but was brushed off by Naofumi for now. Raphtalia's Ancestor expresses her surprise at being reborn as Raph-chan II and warns Naofumi that the vassal weapon battle was not yet over.

Finally, Naofumi heads to the village to find everyone okay. It turns out that Rishia had received the official Vassal Projectile weapon. After finding everyone in one piece, they then travel to meet up with Trash.

Chapter Twelve: The Execution
In the fallout of the invasion, Melromarc was able to capture the rest of Takt's harem and free those he tricked. However, Malty was able to remove her slave seal and escape. At the execution, Takt and all of his followers were reset to level 1 and interrogated. Takt watched his followers die painfully as he was unwilling to say who he was working for. Notably, Takt's sister, who was also a fervent believer, was killed in front of Takt. However, he was still unrepentant and asked to an unseen entity for a do-over.

Tired of his arrogance, Naofumi shows Takt a creature that had been eating the souls of the executed (which prevents reincarnation). Fearful of his existence, Takt is about to reveal information about his benefactor when his head suddenly explodes.

Epilogue: Vanguard of the Waves
Naofumi talked with the remaining heroes and makes preparations to research into the enemy behind the waves and fight it. Unexpectedly, Naofumi receives news that Ethnobalt has come to the village from his world. The injured hero brings news of an evil vassal weapon holder from his world has been steal the vassal weapons and kidnapped Kizuna. Naofumi decides to go to Ethnobalt's world, reunite with Raphtalia, and defeat this new enemy.