The series begins when the servers go live. Nick signs in to Sword Art Online as the character Rythin, enjoys himself for several hours, and then realizes he can't leave the game itself.
Nightblade follows the course of the Aincrad arc, tracking Nick as he tries to survive the death game. The second story, Nightblade II - Wings of Vengeance is the Alfheim arc. The third story, Nightblade III - Defining Strength follows all of season two, Phantom Bullet, Calibur, and Mother's Rosario. There is also a collection of short stories named Nightblade - Sidequests.
The fourth story, Nightblade IV follows Nick's adventures into the world of Assassination Classroom as part of his healing in the Soul Translator. Book One - Viper's Bite and Book Two - Viper's Kiss are completed, with Book Three - Viper's Eclipse currently ongoing.
Nightblade - Brave Song is also a thing, adapting the Ordinal Scale Movie into the Nightblade universe.
There's also a completed non-canon side story series called Nightblade Gaiden, which details what would happen if Nick dated some of the other girls.
Tropes found in this fanfiction:
- The Ace: Kirito. Nick, too, later on, due to his intellect.
- Always Someone Better: Kirito is this to Rythin. Rythin doesn't mind all that much.
- And Your Reward Is Clothes: As in canon, Kirito's reward for beating the first boss is the Cloak of Midnight.
- Animal Motifs: Felines and serpents for Nick.
- Ascended Extra: Argo is one. The info broker had one appearance in the show; in the stories, she's a very important character, becoming Nick's girlfriend at the end of Nightblade.
- Asexuality: Revealed halfway through Nightblade, Nick is asexual. This causes a fairly large amount of emotional instability at first, but Nick doesn't make a big deal about his orientation once he gets over it.
- Author Avatar: The author outright states at the end of the first chapter that Nick is based off of him.Author's Note: As it is a self-insert, I did model the character Rythin and his player off of me.
- Aw, Look! They Really Do Love Each Other: Despite how Nick and Shino act towards each other, they do really care for one another. As implied in the final epilogue for Viper's Kiss that Nick, Kana, and Shino have entered into a polygamous relationship.
- Awesomeness by Analysis: How Rythin does most of his fighting. He's not as strong as Kirito or as fast as Asuna, but he's extremely smart. It's mentioned in passing that he's one of the top students in his grade without studying, and could be the best if he'd just put some effort in.
- Berserk Button: Whatever you do, do NOT harm anyone who Nick actually cares about. It has ended badly for many in the past and it will end badly for you too.Nick: If you touch any of them again, I will kill you. I don't care what I will have to do, or what happens to me, you will be dead by my hands.
- Beyond the Impossible: Rythin still fights and almost kills Kayaba after being paralyzed. It's implied this happens because Rythin has snapped mentally and the signals sent from his NerveGear aren't being interpreted correctly.
- Bloodless Carnage: Inside the game, the only indicator of damage is the red marker. Very much averted when Sugou cuts Nick open from shoulder to hip with a knife and Nick passes out from bloodloss several minutes later.
- Brilliant, but Lazy: Nick is pretty lazy when it comes to studying and doing actual school work, but is still top of his class without much effort.
- Broken Ace: Nick has a lot of mental problems, such as depression, a severe lack of self-esteem, and abandonment issues. It's implied that he basically turned himself into a Type Two so that he didn't have to rely on anyone else.
- Casual Danger Dialogue: Rythin and Kirito engage in banter occasionally while fighting together. Most notable during the assault on the World Tree.
- Color-Coded for Your Convenience: Name dropped in Vipers Kiss.
- Combat Clairvoyance: Rythin gets a version of this halfway through Nightblade. His Unique Skill, Future Step allows him to see anything the system assists, such as enemy attacks, Sword Skills, and the area of effect for spells.
- Crossover: Viper's Bite/Kiss is set in Assassination Classroom.
- Deadpan Snarker: Nick's favored form of communication. His Inner Monologue claims that after people have been exposed to him for long enough, they either develop this trait or start ignoring him, and it shows.
- Defensive "What?": Has happened a few times where Nick has to do this, most notably when 3-E class finds about his scar from his encounter with Sugou.
- Deuteragonist: Rejoice Argo fans, not only is she an Ascended Extra, but she's the deuteragonist by virtue of being Nick's girlfriend, not to mention lots of sections told from her point of view.
- Disguised in Drag: Nick owns a few different accounts in ALO, a few of them are female characters for the purpose of snooping around and doing some investigative work.
- Don't You Dare Pity Me!: Nick despises being pitied and goes out of his way to avoid such empathetic feelings towards him. Pitying him can either make him severely defensive or push his Berserk Button sending him into a Tranquil Fury depending on who you are.
- Doomed by Canon: The Moonlit Black Cats.
- Doorstopper: As of the finish of Viper's Bite, the entire series is sitting at 1,250,718 words in total.
- Dragged into Drag: Has happened a few times over the course of the series. Once over the course of the "Big Sisters omakes and another time in the Asuna Gaiden route. Argo herself has even forced Nick into drag during a shopping trip.
- Even Evil Has Standards: Nick might be a sociopath, but he is disgusted and horrified when Asuna tells him and Kirito that Sugou tried to rape her.
- Facepalm: Nick does this on occasion, especially when someone says something incredibly stupid within earshot.
- Family of Choice: Nick tends to think of the SAO crew as his family, and commonly refers to them as such.
- First-Name Basis: Both averted and played straight in Nick's case. He dislikes people using his name regardless of how close they are to him and uses the screen name of people he isn't close to, but will use the real name of people he thinks of as family.
- Flash Step: Rythin does this at times due to his high AGI stat, the stat that governs max speed.
- Food as Bribe: Kana and Nick are very prone to taking food as bribes, especially Nick.
- Fragile Speedster: Rythin's build in most of the games he plays: he's quick, but can't take too many direct hits.
- Friends Are Chosen, Family Aren't: Building on Family of Choice from above, while Nick thinks of his friends from SAO as family he thinks less of his actual family. Even going so far as to not even want Kana to meet his father.
- Friendless Background: Nick, the loner.
- Genre Savvy: Nick, very much so. Kana to a lesser extent, but still up there with Nick.
- Good Is Not Nice: While Nick can play nice, it's really not him to be the beacon of morality.
- Hates Being Touched: Rythin, obviously. While he's grown more lenient about this over the course of the series, if you're not Argo or one of his closest friends this can be enough to trigger his Berserk Button, though depending on how bad his mental state is this may apply to them as well as showcased in a chapter of Sidequests.Asuna: Rythin... are you alright? You seem... angry.
Kirito: More so than usual?
Rythin: It's nothing.
Asuna (placing a hand on Rythin's shoulder): Rythin, if there's anything-
Rythin: Don't touch me! Don't ever touch me!
- Heroic BSoD: There's been a few times, granted many of them were non-canon.
- Honorary Uncle: Nick to Yui. Also, Kirito to Din, the AI Nick creates using Yui's code.
- I Just Want to Have Friends: Nick's main fear is to lose the friends he's gained.
- Kindhearted Cat Lover: Considering Nick pretty much acts like one, this isn't all that surprising. He loves his cat Emmit.Nick (To Asuna): So as long as you don't kill me, Kirito, or my cat, I think I'll be fine.
- Knife Nut: Nick, especially after he gets the titular Nightblade.
- Lack of Empathy: Nick is literally incapable of feeling empathy. Downplayed in that he's aware of this and tries to act like he thinks people should.
- Lampshade Hanging: Comes with the territory of Nick and Kana being Genre Savvy.
- Living Emotional Crutch: Argo/Kana for Nick.
- Love Bubbles: Happens to Kirito and Asuna whenever they're together, according to Nick.Nick: Like you and Kazuto are any better. Nothing but lovely-dovey fluff, all day everyday. I swear I can see sparkles around you two whenever you're being adorable together. Feel like it's always springtime.
- Love Confession: Asuna gives one to Rythin, but is rejected by the latter. Later on, Rythin to Argo, and this one sticks.
- Mock Surprise Reaction: Rythin has a tendency to do this sometimes when met with a result he has mostly figured out or correctly saw coming ahead of time, most notably when he guessed Leafa's real identity after failing World Tree for the first time.Leafa: But... that means... oh my god. Is that you? Kazuto?
Rythin: Surprise, Suguha, the person you let yourself fall in love with, to forget your previous heartbreak? It's Kazuto. Funny how things turn out, isn't it?
- Mood Whiplash: Knight is very fond of this throughout the entirety of the series.
- Not So Different: Kayaba awards Rythin with Future Step for being the player the most promise. Or in his own words the most like him.Rythin: Why did I receive Future Step?
Kayaba: Future Step? That was a gift to the player with the most promise; the calmest and most calculating player in the game. The person most like me, I suppose.
- Oblivious to Love: Rythin. Argo falls in love with him and he doesn't notice for a full year despite fairly frequent interactions, only learning about it after he confesses to her. He determines he's in love through process of elimination.
- Poisoned Weapons: The Nightblade, a very rare dagger, is physically weak but has a high chance of inflicting a deadly poison on anything it wounds.
- Precision F-Strike: Nick rarely swears (at the beginning) so when he does things aren't good. Even after he gets slightly more foul-mouthed, he doesn't audibly swear very much.
- Protectorate: Rythin swears he will do anything in his power to keep Argo safe. He really does mean anything.
- Red Baron: Rythin's title, the Diamond Tactician. When he hears it, he complains that it sounds stupid.
- Saying Too Much: Nick accidentally mentions he has a girlfriend to E Class in order to get out of the "Which girl do you like?" talk. This causes a whole different set of embarrassing moments for him.
- Shoulder Teammate: Much like Yui, Din likes to take this position on Rythin from time to time during less combat orientated moments and when he's not flying.
- Snark-to-Snark Combat: When Rythin and Lisbeth are in a scene together, this is more or less how they'll be communicating until Asuna thinks they've gotten out of control.
- The Sociopath: Kayaba, as per canon. Nick as well, but far more high-functioning and realistic (since he is aware other people aren't like him and envies the ability to form deep friendships).
- The Stoic: Nick, by virtue of being a sociopath. While he literally can't feel guilt or remorse for things he's done, up to and including murder, the rest of it is learned as a coping mechanism with abandonment. He gets better and more expressive as the series progresses, thanks to his friends.
- The Strategist: Rythin's role, most of the time due to his intellect. He tends to leave the raw manpower to Kirito and Asuna while commanding them from a step back. That isn't to say he's not just as skilled a fighter, though.
- Take That Me: Nick has a habit of insulting himself just as much as he does others.
- Tranquil Fury: Rythin usually goes into this when his Berserk Button is pressed, shutting off all emotions and removing whatever pressed the button. One notable example was when it was hammered:Nick: I am so angry right now that I am beyond anger. If Sugou was in this room right now, I would kill him in a heartbeat with my bare hands and I wouldn't give a damn about the consequences. I would crush his throat with my bare hands and watch him die in satisfaction. That's how angry I am.
- True Companions: The main cast develop into this. Nick especially relies on this because these are the only people in the world he trusts and cares about.
- Unreliable Narrator: In part of Nick's insanity, he may view things differently than what actually happened as shown, notable examples being the Omake "Nick's Mind" from Sidequests and Karma's third person view of him in the last chapter of Viper's Bite. It was even lampshaded by Knight himself.Author's Note: Why yes, Rythin is a rather unreliable narrator, why do you ask?
- Wham Episode: Nick DYING in chapter one of Viper's Bite.
- The Yuuki moment as well.
- What Could Possibly Go Wrong?: Rythin's Famous Last Words before realizing something did go wrong with his avatar after converting to GGO during Gaiden.Rythin: Don't worry, well be fine. Nothing's gonna go wrong.
Rythin: Something went wrong, I am definitely not fine.
- What If?: The whole point of the non-canon side-story Gaiden. Also, the side-quest Twisting Time.Nick: What're your thoughts on parallel worlds?
- You Are Not Alone: In Nick's Darkest Hour, Rika of all people, pulls him back into reality by assuring him that they all do truly care for him.Rika: God, Nick, we've been worried about you. You've been so distant lately, and then Yuuki tells me you were saying something about wanting to DIE. We care about you, you idiot, don't you get that? We all love you. Maybe not the same way we love Kazuto, but we still love you, damn it! You're our big bother! I don't want to lose someone else!
- You Called Me "X"; It Must Be Serious: During Sugu's Gaiden route Argo calls Rythin by his real name instead of his IGN.Argo: Ry, I'm gunna send ya some pics. Don't freak out, 'kay?
Rythin: I don't want your underwear pictures, Argo.
Argo: I'm serious, Nick.
Rythin (interally): Kana?