Spoilers marked for quotes taken from text after the end of the anime (even if spoiled elsewhere on this site).
- "From an endless time and an immeasurable distance."
- While practicing for Theia's play, Koutarou recites the Blue Knight's historical response to the Silver Princess's query about his origins. Oddly, Kiriha reminisces that this is the same response that her fondly remembered big-brother figure ("Onii-chan") gave her ten years earlier, Volume 4/Episode 7
- "The sword is a knight's soul because of the vow placed on it! What can't be broken is that vow, not the sword itself."
- Theia lectures Koutarou on the meaning of a knight's vow, Volume 4/Episode 7
- "There are some things you just can't do! This is a place where people come to make memories!"
- Koutarou, defending the roller coaster from the People of the Earth's radical faction, Volume 6.
- Clan: "Ha! You think you can protect everything? You can't even protect your friends with just that sword!"
- Koutarou: "I'll protect them all! I have to make sure they all succeed with their invasions!"
- Koutarou's defiant defense of the Invaders as he rushes to stop Clan's Super Space-Time Repulsion Shell from destroying him, the Invaders, and the surrounding area, Volume 7
- Farewell, Koutarou. And please stay safe.
- Something inside Harumi recognizes Koutarou has disappeared, even though she's still on stage in the second Blue Knight play, and not behind the school watching the unfolding battle, Volume 7
- "No, this isn't a parting. Everything is about to start."
- Theia, upon Koutarou's return from the unknown, Volume 7
- Also arguably a meta truth.
- "I hope the first star shines blue... just like Koutarou's armor..."
- The Goddess of Dawn's version of "Let there be light", Volume 7.5
- "...people are going to die! Can you still call yourself a princess of Forthorthe knowing that and doing nothing about it?"
- Koutarou, expanding to Clan on the risks, consequences, and responsibilities of a time traveler's foreknowledge, Volume 7.5
- And this is probably the part of him that Theiamillis-san trusts so much.
- Clan's thought in response, Volume 7.5
- Koutarou: "But Your Highness, Maxfern is a criminal."
- Alaia: "I know. But if he can establish a good government, I won't mind. What's important isn't my pride, but the lives of the citizens."
- Alaia demonstrates clearly why she is the most beloved ruler in Forthorthian history, Volume 7.5
- "Your Highness, to a model knight, his sword is everything. Yet even if that sword were to break, so long as the oath sworn upon it remains unbroken, then the sword is still considered unbroken too."
- Koutarou, putting into words the fealty, trained into him by Theia, that made the Blue Knight the most beloved knight in Forthorthian history, Volume 7.5
- "Layous Fatra Veltlion. In this urgent situation without an empress, I, Princess Clariossa, will act in her place. This is a royal command. As a knight of Forthorthe, do what you must!"
- Clan, unleashing the hounds of war in the form of one well-armed earthling high school student on the Coup d'etat platoon that poisoned the town's water, Volume 7.5
- A full platoon - commander, 36 sword infantry, 5 magicians, and a magical golem.
- Lidith: "Lady Pardomshiha, just who is that person?"
- Flairian: "That's... what I want to know."
- Lidith: "That sword and armor... Based on their strength, they must have been made with alchemy."
- Fauna: "It looks like he's using spiritual energy, to... read the auras of his opponents (and) to improve his speed."
- Claris: "That man is using magic, too... I don't know if the Blue Knight actually cast the spell himself or not, but at the very least, he's ... had regular access to powerful magic."
- Princess Alaia's retainers, marveling at the fighting style and weapons of the Blue Knight, Volume 7.5
- Theia, nothing like this was in the play!
- Koutarou's favorite epithet in ancient Forthorthe, Volume 7.5
- "Maxfern indiscriminately poisoned an entire village in order to capture me. I can't imagine that someone like that would build a good government."
- Alaia, recognizing that she must prevail, Volume 7.5
- If I hadn't been here, the disease couldn't have been cured. If I hadn't treated the virus the way that I did, there's no reason I should be resistant to it... And it's certainly true that that man's an endless time and immeasurable distance away from home...
- Clan makes a literally history-shattering observation, Volume 7.5
- In context: The water supply "poison" turned out to be a fast-acting, water dispersed virus. After an intense effort, Clan develops a genetically engineered cure that delivers genes from Koutarou, who is immune to the virus, to the local affected population; this is informed by her own partial immunity. She has this revelation when she can finally slow down - the historical "antidote" to the "poison" would not have been possible had not both she and Koutarou been displaced through time. The capabilities of Koutarou's modern Forthorthian powered armor match the magical properties attributed to the Blue Knight's armor. The story of the Blue Knight was always their story. In addition, this was a Chekhov's Gun for Volume 25 - identification of Koutarou's genes dispersed through the modern Forthorthian population was one of the key factors verifying Koutarou as the original Blue Knight.
- This man's lies aren't scary at all.
- Maki, who detests all dishonesty, learns a truth about Koutarou, Volume 8
- In context, Maki seriously misunderstands Koutarou after the events of Volume 5/Anime episodes 8 and 9. For most of Volume 8, she has held him under a truth spell that alerts her if he lies. After several conversations that smash her preconceptions into shatters, Koutarou finally tells a lie: when the ice demon attacks Maki and Yurika (who ends up encased in ice) at the ski resort, after healing Maki's fatal wound with Signaltin, he loaned her his jacket. When he started sneezing, she asked if he wanted his jacket back; he denied he was cold. After this, Maki didn't need a spell to know Koutarou was lying when he claimed he'd abandon Yurika as part of an effort to convince Maki to go to safety herself.
- He may be the only man to ever have four princesses fawn over him so.
- Clan, reflecting on the feelings of Theia, Alaia, Charl, and herself, at Koutarou's sickbed, recovering from the first fight with Alunaya, Volume 8.5
- "I am Alaia, the silvery white snow of Mastir! Oh holy sword of the temple, carve my name into your blade and revive!"
- The conclusion of the ceremonial Ancient Forthorthian spell to activate, or reactivate, Signaltin, Volume 8.5
- Your Highness, our Blue Knight ... is the real one.
- Ruth, reflecting on what she learned when Koutarou rescued Theia, Volume 9
- "He was using the sword's power to summon the girl's dead mother so that they could meet in her dreams." He didn't just let the two of them talk. He actually allowed them to meet and touch one another... to think anyone would use necromancy in such a way...
- Rainbow Nana learns that there are good uses for even the most abhorrent of magics, Volume 10. Gets a callback as she remembers her first meeting with Koutarou in Volume 35.
- "It's Signaltin. Even though we'll be frozen here for ten years, that sword will still be in this city. That sword has always been protecting you."
- Clan identifies the source of the mysterious white mana that has been protecting Koutarou and the Invaders, Volume 10
- "I promise you, Onii-Chan! Kii will never let you feel lonely! Kii will always be by your side!"
- Kii-chan comforts the still time-traveling Koutarou after he reaches the site where he witnessed his 6-year-old self sitting in shock next to his mother's body after the car accident, Volume 10
- In context: this is just after Koutarou interrupted his rush to the accident site to rescue Kii-chan from Maya's murder attempt on behalf of the Radical Faction. Six-year-old Kii-chan does not understand - doesn't even seem to consider - how he knows when and where his mother will die, and lacks the context to understand the scene in front of her. But she is very much aware that Koutarou prioritized saving her life over saving his mother, with all of the nascent perceptivity that will make her the most formidable Invader, and the empathy she feels from losing her own mother so recently. It is no wonder that she devoted her life to preparing to meet her "Onii-Chan" again, to keep her promise that he will never be lonely.
- "So please tell me, Koutarou! Is the owner of this necklace still happy? He's not feeling lonely... is he?"
- Modern-day Kiriha making good on Kii-chan's ten-year-old promise and recognizing that she still has a chance with her First Love, and best friend, Koutarou, Volume 10.
- "Love is all."
- The self-styled First and Last Invader, comforting Sanae's spirit as it goes to be reintegrated with her still-living body, facing the fear of forever forgetting Koutarou, Volume 11
- "We're all using our own ways to invade Koutarou's heart."
- Kiriha, expressing what now unifies the Invaders, Volume 11
- "Not even a lesser god should have this much power."
- The Ghost Girl learns Sanae's true power after her body and spirit are fully integrated with both sets of memories intact - specifically including her ghost-form memories of how to control her spiritual energy, Volume 11
- Sanae: "Death isn't the end... And you won't be alone. Someone somewhere out there is watching over you..."
- Ghost Girl: " Will there be a next time for me?"
- Sanae: "There's no way there wouldn't be... I don't think the god of this world is that unforgiving."
- Sanae comforts the dying Ghost Girl, Volume 11
- Goodbye, Harumi... We will probably never meet again. Live your own life... and if possible, stay with him this time... until the end...
- Alaia's spirit formally bequeaths control of Signaltin to Harumi, the normal girl into whom she was reincarnated, Volume 12
- Elle, if you say any more than that, I swear I'll punch you even if you are the empress.
- Koutarou greets an old friend with whom he shares a secret, Volume 13
- Koutarou: "My power is insignificant. It's all borrowed from other people.
- Elexis: "Your true power is not something that can be seen. It allows others to entrust their powers to you. It is your very existence."
- Koutarou: "Then I will take pride in that true power. And I will never betray the trust placed in me."
- The creed of the one true Blue Knight made plain, Volume 13
- "We're staking our lives on this because our hands have been connected for so long."
- Koutarou invokes The Powerof Friendship as the Invaders stand with Theia against Elexis and the modern Coup d'etat forces, Volume 13
- "I am Alaia, the silvery white snow of Mastir! Oh holy sword of the temple, carve my name into your blade and revive!"
- Harumi invokes Ancient Forthorthian magic to share Signaltin's mana with the Blue Knight's similarly named energy weapon, Volume 13
- "There is only one person in this world who I've asked to make me her knight. Theia, you are my only princess."
- Koutarou responds to Theia's self-doubt when he confirms to her that he is the historical Blue Knight, Volume 13
- "I am Maya. Just like you, I fought against that boy alone and lost."
- And that's the story of how Maya and Elexis met, Volume 13
- "Koutarou, live the way you wish. Laugh, hate, cry, and love as you please."
- Theia's standing order to Koutarou, Volume 14
- I am known as the emperor of fire dragons. Shizuka, I will trust you with my overwhelming power, and you may use it to protect whatever you wish.
- Alunaya formalizes his bond with Landlord-san, Volume 14
- "That girl is Theiamillis's mother."
- Clan tells Koutarou that things have gotten complicated in 20-year-ago Forthorthe, Volume 14
- "May the knights who left for the other side of the sky rest peacefully. Let none disturb their sleep."
- Inscription on the monument left by Alaia, to guard the Blue Knight and Clan, "his assistant." while they rested through the endless time portion of their journey home, Volume 14
- Elfaria at first thought it was a memorial to all of the war's honored dead.
- Koutarou: "... we couldn't change history. I know we had to do this, but ... even then, it's so hard."
- Clan: "It is, Veltlion. It really is."
- After finding the monument; the time traveler's lament at the beloved friends who were left behind, Volume 14
- "It's him?! The Blue Knight maniac — random sound of surprise or anguish!"
- A common response of Forthorthian coup d'etat forces on encountering Koutarou for the first (and last) time; maniac is intended by the speaker(s) in the context of cosplaying meddler, Volume 14
- Koutarou: "Was Theia coming to this room your doing?"
- Elle: "Yes. I was the one who sent Theia here. Because I knew you were here."
- The saga of a mother who helped re-engineered history to protect her daughter - and her ancestors, Volume 14
- "You still fight. For everyone, and for their future. So I will too. I want to stay by your side and do what you do."
- Harumi, expressing the Invaders' common sentiment regarding Koutarou's battles, Volume 15
- Maguz: "Using force, I will reclaim our home. (I have named myself for) a true ruler, a legend who bravely chose to fight. His name was..."
- Maya: " Maxfern."
- The readers learn that the People of the Earth and the Magical Kingdom of Folsaria descend from the banished leaders of the Coup in Ancient Forthorthe, Volume 16
- You did well to come, my boy!
- While perfectly capable of murder in her own interest, Maya doesn't like Maguz, Tayuma, or their way of doing things, and celebrates Koutarou's rescue of Kiriha, Volume 16
- This looks similar to one of Forthorthe's family crests... but which one was it?
- Elfaria misses a clue at the archaeological site where Koutarou works, Volume 17
- "I've finally come to understand how you're doing so well on your own, Koutarou. It's thanks to these girls."
- Satomi Yuichirou, Koutarou's father, praising the Invaders after meeting them, Volume 17
- Kiriha: "You haven't realized, have you, Koutarou?"
- Koutarou: "Realized what?"
- Kiriha: "That you treasure us more than a normal boyfriend would treasure his girlfriend."
- Kiriha states the growing truth, Volume 18
- "I don't believe it! Is that even possible! ... (Clan, Sakuraba-sempai, take) a good look at that castle! Don't you recognize it!...This was my battle from the very beginning!"
- The Stable Time Loop finally closes. Koutarou, on discovering in the Magical Kingdom of Folsaria the castle from which Clan dispatched the ancient Coup d'etat leadership with her second time-space weapon, learns that everything that has happened to him since the start of the Invasion is tied to the decisions he and Clan made, and the actions they took, in Ancient Forthorthe, Volume 19
- The promised time is near ... In order to protect free will, I will not brook interference.
- The First and Last Invader takes the field against the Whirlpool of Chaos summoned by Dark Purple, Volume 19
- "It is indeed possible for Forthorthians and Earthlings to have children together."
- Clan relieves what may be Theia's greatest worry, Volume 21
- "So you'd stand in the way of the royal family once more, Maxfern and Grevanas... This is all my unfinished business as far as I'm concerned. I have to go and settle it."
- Koutarou recognizes the Blue Knight and Silver Princess's adversaries in synchronicity with the leaders of the modern Coup d'etat, Vandarion and Granado, and sees a duty to conclude the matter once and for all in modern times, Volume 21
- "There is one thing I know for certain. That girl ... She's a true princess of Forthorthe."
- The commander of the Coup forces opposing Theia on the battlefield can find nothing but praise for her, Volume 21
- Hitting the fifteen person infiltration team with three potentially lethal attacks - the third replacing the lethal payloads with paintballs, reinforced both her intent to capture them alive and unharmed if at all possible in true Forthorthian chivalry dating back to the legend of the Blue Knight and Silver Princess, and her ability to single-handedly kill them all if they continued to oppose her.
- Corona Convention Article 24: "Those who have ratified the Corona Convention are strictly forbidden from reentering the atmosphere without the use of a spaceship. Under extreme circumstances where no other alternatives present themselves, it may be considered as a last resort so long as all other ratifying parties agree to it."
- Yurika's Postscript: "I won't even consider it! I'm never letting that happen again."
- As if Yurika's opposition will prevent Theia, or Koutarou should it come up in the future from putting themselves at risk in low planetary orbit to save someone else's life, or stop her from helping in the time of need Volume 21 Postscript
- "I'll be your backup, Koutarou-kun."
- Elexis, Maya, and Darkness Rainbow join Koutarou in the field to assist against Vandarion's biological weapon attack against the civilian population, Volume 22
- "W - Wait, I can do something!"
- Yurkia fully comes into her own, using a combination of magic spells to contain and destroy Vandarion's biological weapon, Volume 22
- "Your Highness, just who is that knight in blue armor that you brought with you?"
- Reporter Danesford Laren asks Theia the one question she doesn't want to answer, Volume 24
- "This boy is neither the descendant nor the successor to the Blue Knight as we had suspected. He is none other than the Blue Knight himself."
- After circumstances change, Royal families spokesman Lord Karlstoff finally answers the question, and thereby rocks the very foundations of the entire Holy Forthorthe Galactic Empire, an intergalactic culture built on two thousand years of lionizing the Blue Knight, Volume 25
- "There's two thousand years of interest on (the Blue Knight's) two thousand years of salary! I can't even imagine what the balance due is! ... Koutarou has become the biggest creditor in history! You could call that empty bank account a second Signaltin created by Alaia the Silver Princess!"
- Elexis realizes that Alaia's trust of, and love for, Koutarou created one last, completely unstoppable, trump card over threats to Forthorthe, Volume 25
- "I am still a princess of Forthorthe. No matter what I lose because of it..."
- Ceilēshu acknowledges the price she must pay for defying Elexis to help Koutarou - the loss of Elexis's aid to heal her ill father, Volume 25
- Ceilēshu: "How was it that Alaia-sama shook off her hesitation?"
- Clan: "Alaia-san loved both Forthorthe and that man. That's why she was able to do everything she could for them."
- The Power of Love accounts for both the victories in Ancient Forthorthe, and on Earth, Folsaria, and Forthorthe today, Volume 25
- "You really are more gentlemanly when you're incredibly angry. And when you're angry, you don't lose to anybody. That's historical fact."
- Clan summarizes the consequences for anyone who threatens the people Koutarou holds dear - thinking first of herself (in Volume 4, Anime episodes 6 and 7), Volume 25
- "You really are an ideal knight, aren't you? If you so wished, you could rule everything."
- Elexis notes the difference between himself and Koutarou, Volume 25
- "Over 99 percent of the spiritual energy in this area is being controlled by the Blue Knight now! He's even taken control of the spirits I had under my spell!"
- Dark Purple learns the futility of using necromancy to attack the Blue Knight in a two thousand year old Forthorthian military cemetery, where the first burials were people Koutarou fought alongside, and watched die, in Ancient Forthorthe, Volume 25
- "The area around Koutarou is sacred ground. Bullets won't fly straight!"
- Elexis partially misunderstands Koutarou's protections; If Sanae had been there, she would have seen (the ghost of an ancient Forthorthian) knight protecting Koutarou with his shield, Volume 25
- Koutarou: "Why didn't you use any huge weapons or major explosives?"
- Elexis: "In the middle of the suburbs? Don't be ridiculous. The casualties would be too high."
- Koutarou: "It might not have been so bad to lose to you after all."
- Koutarou acknowledges Elexis as a worthy opponent, Volume 25
- Maya: "... the stars are beautiful."
- Elexis: It's the perfect weather for a voyage, isn't it?"
- Maya: "Heh, let's leave it at that..."
- After attacking Vandarion to assist Koutarou, the last recorded words from their powerless spacecraft drifting away, never again to be seen, Volume 26
- The Nine Invaders, telepathically, in unison: "Do you love us as...you know, women?"
- Koutarou: "Of course I do!"
- The revelation that made all of the difference, Volume 26.
- "My name is Invader!"
- To Clan goes the honor of declaring the Name under which the Nine Invaders will invest The Sword of Harmony, Volume 26
- "Please don't be sad, Koutarou-sama. Just ... please find the me that will forever live on within Harumi.
- The portion of Princess Alaia's spirit that had been powering Signaltin, freed by the new contract with the Invaders bids farewell to Koutarou as her identity passes into the light to join Charl, Flair, and her contemporaries, and the remainder goes to make Harumi's soul whole, Volume 26
- "We have breaking news. Just moments ago, the government ... announced that envoys of a nation from another galaxy, the Holy Forthorthe Galactic Empire, have come here to Japan to establish diplomatic relations."
- One newscast changes the whole world, the nation of Japan, and the lives of Koutarou and the Invaders forever, Volume 28.
- "Would Princess Devil-san and her attendant happen to be from Forthorthe?"
- Kenichi of the Sun Rangers figures out part of what is going on, Volume 28
- I see... the promised time has come. The time for our final trial.
- Maki recognizes what is happening when she she suddenly disappears, volume 28
- "Don't worry, Harumi. Fate is on your side."
- Kiriha, next to last of the Invaders to disappear, makes a bold prediction, Volume 29
- "Crossing endless time and immeasurable distance ... it was all so that you — that we — could reach this conclusion. Please don't forget. We love you."
- In the end, all Nine invaders reach out to Koutarou through Harumi as she disappears to join them, Volume 29
- "What are you saying, Satomi-kun? Didn't you make a promise with everyone that you'd go to the nationals this year?"
- Kashiwagi Shiori gives Koutarou a vision of what his life might have been like without the Invaders, Volume 29
- Koutarou: "So it was all for this moment. For me to understand your circumstances and solitude, and to face you without any fear?!"
- The Goddess of Dawn: "I wanted you to accept me ... to accept us ... of your own free will."
- Koutarou finally understands the conditions of the trial prepared for him by the Goddess of Dawn from before the beginning of time, Volume 29
- "What are you doing? You're coming too."
- Koutarou refuses to let the Goddess just abdicate her powers in favor of her Nine Avatars, Volume 29
- "A knight's benevolence does not discriminate, not even with the Goddess of Dawn. Satomi-kun always surpasses expectations. He did two thousand years ago, just like he is now, and just like he surely will in the future.
- Harumi, as the ten Invaders start back to Corona House at the end of the final trial, Volume 29
After the Final Trial (Volume 30 -
- Kenji: "Kou, what's going on here?"
- Koutarou: "Well, it's complicated."
- Kenji: "You're telling me, Kou! Highashihongan-san over there is freaking flying!
- Kenji (later): "I had no idea Kou was this strong..."
- Kotori: "Kou-niisan is ... It's like that play came true..."
- Kenji and Kotori discover that they've been Locked Out of the Loop for two years, Volume 30
- "It's not who your enemy is that matters. It's who you won't betray."
- Koutarou, Volume 30
- "That's it, Ruth-san! Use the combination!
- Koutarou cheering for Ruth against Shizuka in the Kabutonga beetle costume finally reassures her that Koutarou loves her more than beetles, Volume 31
- "What a mess. I even pointed a weapon at Kii... I'm glad I lost. I really, truly am."
- The reformed Clan laments attacking Koutarou and Kiriha after learning that Kiriha is the aged Kii-chan, in the alternate world where Clan pairs with Koutarou, Volume 33
- Koutarou: "I feel like I'm not really doing anything here."
- Harumi: "In the same fashion that sails do nothing, perhaps you could say that. But a ship nevertheless needs them to move. The same way we need you, Satomi-kun."
- It is the combined strength of Koutarou and the Invaders that ultimately wins their conflicts, Volume 39
- Unnamed, most likely Harumi: This is the result of him accepting all of us... so why does Satomi-kun feel he has to choose just one wind to propel him into the future?
- Unnamed, almost certainly Theia: Because he's an idiot.
- Unnamed, most likely Ruth: Your Highness, you don't have to say it that way!
- The Invaders telepathically comment on Harumi's metaphor - and Koutarou's insistence that he can wed only one of them, Volume 39
