''[[https://www.fanfiction.net/s/9892113/1/Field-of-Innocence Field of Innocence]]'' is an ''WesternAnimation/AvatarTheLastAirbender'' {{Backstory}} fic that fleshes out Iroh's son Lu Ten (who, despite his impact on his father, is [[SmallRoleBigImpact barely mentioned in the show]]), and shows his relationship with his family, especially his role as a BigBrotherMentor to Azula and Zuko. It was completed on November 2015.
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!!Tropes:
* AbsurdlySharpBlade: Lu Ten's swords Jianhuren can deflect and even slice through stones without taking damage. Justified, as they're made from dragon claws.
* AbusiveParents: Ozai, as in canon, abuses the hell out of his kids. His first appearance in the fic is expressing how much he doesn't regret burning a handprint into five-year-old Azula's back for disappointing him during training.
* AccidentalTruth: This exchange before the final battle at Ba Sing Se combines this with {{Main/Tempting Fate}}, to absolutely ridiculous levels.
-->'''Iroh''': Take a good, long look at it, Lu Ten. This may be the last time you see Ba Sing Se.\\
'''Lu Ten''': I have no doubt of it.
* ActionDad: Iroh, before the death of his son.
* ActionMom: Kei Rin before her death.
* ADogNamedDog: Combines with BilingualBonus. Near the end of chapter 2, Iroh says that he's going to go talk with Admiral Teitoku. 'Teitoku' means 'admiral' in Japanese.
** One of Iroh's hawks is named Takamaru. "Taka" is Japanese for "hawk."
* AFatherToHisMen: Lu Ten acts like an older brother to the soldiers under his command as much as he does to Azula and Zuko. [[spoiler: He actually dies protecting a younger soldier from an attack that would have killed him.]]
* AffectionateGestureToTheHead: Lu Ten ruffles Zuko's hair before getting on the ship to the Earth Kingdom.
* AmazonChaser: While in the Earth Kingdom, Lu Ten apparently had a thing for bounty hunter Jun, mentioning her "amazing" skills and strength in his letters home.
** Iroh claims he was initially attracted to Lu Ten's mother Kei Rin when he saw her doing an extremely difficult firebending form perfectly.
* AnnoyingArrows: Vachir and Mongke's arrows only slow Lu Ten down as he fights, and they're not what ultimately finishes him: [[spoiler: Ozai's poison is.]]
* AudibleSharpness: At one point, there's a ''shing'' sound as Lu Ten draws a sword.
* BadassBoast: Lu Ten gives one to Ozai -
-->'''Lu Ten''': Now you listen to me, Uncle, and listen good. If you hurt either one of those kids again, if you say anything to make them feel bad, if you so much as look at them wrong, I will face you in an Agni Kai and ''I will break and humiliate you in front of the whole court.'' I don't care who you are. I don't care if our family is watching. I'll hold nothing back, I will destroy you!
** It actually makes Ozai of all people ''back down.''
* BadassFamily: In addition to being Roku's granddaughter, on the other side of her family Ursa is part of the Yuudoku clan, who traditionally serve as assassins.
* BattleCry: Iroh and Lu Ten do one before charging into battle at Ba Sing Se.
-->'''Iroh''': Warriors of the Fire Nation! This day, with Agni's blessing to give us strength, we end this siege!\\
'''Lu Ten''': For the honor of the Fire Nation, for the good of the world, (draws sword) FORWAAAARD!
* BattleInTheRain: The last battle of the Ba Sing Se siege is fought in the middle of a raging storm.
* BeCarefulWhatYouWishFor: At the very end of one segment, four-year-old Azula decides that she's going to be just like her father, great-grandfather, and cousin. She's right on the [[LikeFatherLikeSon first]] [[TheDreaded two]] [[ManipulativeBastard counts]], but she has no idea what that actually means, only thinking that she's going to be a strong bender like them.
* BerserkButton: Whatever you do, ''never'' hurt Lu Ten's little cousins.
* BewareTheNiceOnes: Lu Ten is a polite, compassionate sweetheart by nature. Threaten his little cousins, however, and he gets ''scary.''
* BigBrotherInstinct: Lu Ten acts like a protective older brother to Azula and Zuko. When he finds out that Ozai has been abusing his children during training, he bolts across the palace to hunt his uncle down, slams him against a wall, and promises to destroy him in an Agni Kai if Ozai so much as looks at the kids wrong. BewareTheNiceOnes, indeed.
* BigBrotherMentor: Lu Ten helps train his cousins in firebending.
* BigWhat: Gisei when Iroh announces that he is surrendering and they will retreat from Ba Sing Se immediately.
* BilingualBonus: The name of the Yuudoku clan's PerfectPoison, ''guówáng wànsui,'' which Ozai gives to Mongke and Vachir to kill Lu Ten with, and which it's implied Ursa later uses to kill Azulon. It means "long live the king," something traditionally said after the death of an old emperor and crowning of a new one.
* BloodFromTheMouth: It's mentioned that there's blood around Lu Ten's mouth as he's dying. Justified, as he's suffered fatal internal damage.
* BreakTheCutie: Happens to Azula when Lu Ten isn't there to protect her from Ozai, and no one else is willing or able to.
* BrotherSisterTeam: What Lu Ten encourages Zuko and Azula to think of themselves as, and what he believes they will grow up to be. It's almost lucky for him he'll never know he is [[CainAndAbel dead wrong.]]
* BurnBabyBurn: Played with when Ozai burns Azula's drawing of Lu Ten. It wasn't important to him at all, but it certainly must have been to her.
* CallForward: Before he leaves, Lu Ten tells Zuko and Azula that, as a BrotherSisterTeam, "the only way you win is together." This is what Azula tells Zuko eight years later when convincing him to side with her at Ba Sing Se.
** When explaining why he's taking her to train at sunrise, Lu Ten tells Azula, "We're firebenders, we rise with the sun." We can assume that he told Zuko that too.
** Zuko's lines from "Zuko Alone" about [[spoiler: his dual swords being two halves of a single weapon]] turn out to be what Lu Ten told him in a letter to always remember if [[spoiler: he wanted to be able to use the swords properly.]]
* CheerfulChild: Azula, before her uncle and cousin leave and Ozai gets to her, turning her into the CreepyChild seen in canon.
* ChildSoldiers: Gisei and Nageki are sixteen, and presumably a good amount of the other soldiers are underage as well. The two of them mention that the minimum recruitment age for the Fire Nation army is fourteen.
* ColonelBadass: Lu Ten has attained the rank of colonel by the time he fights his last battle, like his mother before him.
* CryIntoChest: Azula cries into her mother's chest while breaking down over the death of her cousin.
* CurseCutShort: "Y-You...You sick...twisted...son of a - !" Justified as Lu Ten was so angry and disgusted that he couldn't speak.
* DeclarationOfProtection: "I promise you, [[AffectionateNickname Zula]], [[DoomedByCanon as long as I'm here]], I'll always protect you."
* DidYouActuallyBelieve: Played with. After a seemingly well-meaning Ozai bids them both farewell and good luck on their mission, Lu Ten asks Iroh if he honestly believed all of that. Iroh knows that, even though he wishes it were true, [[{{Jerkass}} Ozai]] would [[OutOfCharacterMoment never act like that and something is up.]] They're both right - [[spoiler: Ozai was just trying to divert suspicion from himself as he plots their deaths.]]
* DiedInYourArmsTonight: Lu Ten dies in Iroh's arms.
* DivingSave: How Lu Ten saves his RedShirt friend Gisei's life [[spoiler: at the cost of his own.]] Apparently this is something of a signature move for him, and he likely [[spoiler: would have survived again if he hadn't been poisoned.]]
* DontMakeMeDestroyYou: What Lu Ten tells Ozai in his BadassBoast. He personally hopes it won't come down to [[DuelToTheDeath Agni Kai]], but is ready and willing to demolish his uncle if it does.
* DoomedByCanon: Lu Ten will die at Ba Sing Se; and with him, any hope that Azula would escape her father's influence.
* DualWielding: Lu Ten ([[spoiler: and later Zuko]]) with his dao swords.
* EnfantTerrible: Iroh implies that Ozai was this as a child, when he says that Azula is [[TurnOutLikeHisFather starting to turn out like her father]] after coming home from Ba Sing Se and seeing how she's changed.
* EvilUncle: Ozai is one to Lu Ten. [[spoiler: The kind that arranges for his nephew to be murdered to clear his way to the throne.]]
* ExtremeMeleeRevenge: Iroh dishes one of these out to the Earth Kingdom soldiers [[PapaWolf when he sees his son lying wounded on the ground.]] He defeats a legion of earthbenders on his own, drives off the rest, and essentially wins the battle singlehandedly.
* FailureToSaveMurder: Azula believes that Iroh's failure to save Lu Ten makes him responsible for his death, and throws it back in Iroh's face that he "killed his own son."
* FamilyEyeResemblance: Iroh mentions that Lu Ten has his [[MissingMom mother's]] gold eyes.
* FatalFamilyPhoto: On the ride to Ba Sing Se, Lu Ten's friend Gisei shows him a portrait of his four younger siblings, and talks about how he can't wait to see them again when he goes home. Coupled with his MeaningfulName, this seems to be clearly setting up Gisei to die. [[spoiler: It's Lu Ten who dies protecting him, which gives him major SurvivorGuilt.]]
* GiveMyRegardsInTheNextWorld: After saying goodbye to Iroh and Lu Ten and the two leave for the ship to Ba Sing Se, Ozai gives a SlasherSmile and says to himself, "Give my regards to Kei Rin when you're reunited, will you?"
* GrayRainOfDepression: It's raining as Lu Ten [[DiedInYourArmsTonight dies in his father's arms.]]
* HeroesPreferSwords: The heroic prince Lu Ten (the Fire Nation's TokenGoodTeammate) wields dual swords. [[spoiler: He later passes them on to his cousin, future hero Zuko.]]
* HeroicSacrifice: [[spoiler: Lu Ten dies taking an Earthbender's boulder in the chest to protect a young soldier that he had befriended.]]
* ICallItVera: Lu Ten named his [[DualWielding dual dao swords]] Jianhuren, [[MeaningfulName which is Chinese for "guardian."]]
* ICanStillFight: Lu Ten tries to say something like this...right before he drops to the ground from all his wounds and doesn't get up again.
* IDidWhatIHadToDo: When Lu Ten faces General How in battle to avenge his mother, How tells him he was only doing what was necessary to protect the Earth Kingdom when he killed her.
* IDontWantToDie: Lu Ten's last thought before dying is, ''Agni, I'm not ready...''
* IllKillYou: Nageki, Gisei's friend who looked up to Lu Ten, yells this when he blames Gisei for Lu Ten's death and attacks him.
* InTheBack: Three of Vachir and Mongke's arrows hit Lu Ten in the back. Two of them don't go in too deeply, though, and he powers through.
* ImpaledWithExtremePrejudice: It's mentioned that General How killed Kei Rin by impaling her on a spike of rock. ''Ouch.''
* ItHasBeenAnHonor: Gisei to Lu Ten before the FinalBattle at Ba Sing Se -
-->'''Gisei''': Colonel, on behalf of all the soldiers under your command, if we don't make it back from the battle today, we want you to know that we believe it is the highest honor to fight by the side of a warrior like you. You are truly great, my prince.\\
'''Lu Ten''': ''(smiles)'' Tell everyone thank you, if you can. And to be completely honest, the privilege of having comrades like you is ''my'' highest honor. [[TemptingFate When this is over, we'll celebrate our victory together.]]
* ItsAllAboutMe: Ozai all the way. Especially in the scenes where we get to hear his train of thought, he ''never'' thinks about anything but his own gain.
** Even when Vachir calls Ursa a bitch, he gets angry not on his wife's behalf, but because ''a possession of his has been insulted.''
* IWasQuiteALooker: When telling Lu Ten, Zuko, and Azula about his late wife Kei Rin, Iroh claims to have been this when he was younger, [[{{Squick}} squicking out]] Lu Ten.
* {{Leitmotif}}: Word of God says that "The Price of Freedom" from [[VideoGame/CrisisCore Final Fantasy VII: Crisis Core]] is Lu Ten's.
* LikeBrotherAndSister: Lu Ten to his cousin Azula. He considers Zuko a younger brother as well.
* LittleNo: Gisei when Lu Ten dies, and Azula when she gets the news.
* LongHairedPrettyBoy: By the end of the Siege of Ba Sing Se, Lu Ten's short and choppy hair has grown out long and glossy, down to his shoulder blades. He's mentioned to be quite handsome, with many fangirls in the Caldera alone.
* MadeOfIron: ''Lu Ten.'' Ozai hires Mongke and Vachir of the Rough Rhinos to kill Lu Ten in battle and MakeItLookLikeAnAccident, but their poisoned arrows (combined with every other thing coming at him) only slow him down, not kill him. However, they do get the job done eventually: [[spoiler: if not for what they'd done, Lu Ten would have survived [[TakingTheBullet Taking The Boulder]] in the chest.]]
* MakeItLookLikeAnAccident: How Ozai arranges for Lu Ten to die.
* ManlyTears: Lu Ten on the ship to the Earth Kingdom, when he can no longer see the Fire Nation.
** Gisei and Iroh both when Lu Ten dies.
* MarkOfShame: When [[spoiler: Lu Ten is killed protecting Gisei]], their friend Nageki blames Gisei for [[spoiler: his death]] and attacks him with a knife, cutting his face multiple times before being pulled off of him. He specifically calls the wounds this in his subsequent TheReasonYouSuckSpeech.
-->'''Nageki''': A failure like you should be branded, so everyone will know how you shame the Fire Nation! This won't ever go away, and neither will those wounds! They'll scar, you'll always see them and you'll always remember, and you deserve it. You deserve much worse than anything I can give you.
%%* MeaningfulEcho: See CallForward.
%%* MeaningfulFuneral: Lu Ten's.
* MeaningfulName: A whole bunch -
** The name of Lu Ten's dual dao swords, as mentioned above, and the name of his tigerwolf, Hakkai, that he rides in the Fire Nation's campaign to destroy the walls of Ba Sing Se. 'Hakkai' is Japanese for 'destroy.'
** Iroh's wife, Kei Rin. 'Kei' can be read one way in Japanese characters as 'respectful,' and 'Rin' means 'cold,' making her cold but respectful, as Lu Ten remembers her acting to everyone outside her family.
** Gisei Seigi, the young soldier that [[spoiler: Lu Ten sacrifices his life to save]]. 'Gisei' means [[spoiler: 'sacrifice']] in Japanese.
** All of Gisei's younger siblings have the names of some kind of weapon.
** Nageki Noha. In Japanese, ''nageki no ha'' can translate to "blade of grief." In his grief over Lu Ten's death, he takes a blade to Gisei's face, saying that he is responsible and deserves to be punished.
** The name of Ursa's family, the Yuudoku clan, assassins who create PerfectPoison. "Yuudoku" means "poisonous" in Japanese.
* MenDontCry: Averted. [[{{Jerkass}} Lieutenant Kotai]] tries to tell Gisei this when he starts sobbing over Lu Ten's body, and Gisei fires back with this -
-->'''Gisei''': And why not?! Why shouldn't I cry?! Forgive me, sir, but it's not right to hold back. The prince...The colonel was my best friend, and my comrade. If a man can't shed tears when his comrades are killed, then that man is heartless! To show that I feel something for my brother in arms can't be weak! This is just one way that I can honor him!\\
'''Kotai''': Quiet! Contain yourself, soldier!\\
'''Iroh''': Enough, Lieutenant. Enough. ''(Both look at him to see that he is crying too)'' Sergeant Seigi is correct. A soldier should never force down his grief.
* MissingMom: Lu Ten's mother, Kei Rin, was killed in battle when he was eight.
* NamesToRunAwayFromReallyFast: The Sunstorm, and as in canon, the Dragon of the West. Lampshaded by Zuko.
%%* NiceGuy: Lu Ten.
** Gisei counts too.
* NothingIsTheSameAnymore: Zuko sadly says this to Iroh after Lu Ten's funeral. Just to recap, in the space of about a week, his cousin was killed, his [[MissingMom mother's gone missing]], his uncle has been disgraced, his father became Fire Lord, and his sister is starting to really get into her role as DaddysLittleVillain. He's absolutely right.
* OhMyGods: Like in [[{{Fanon}} most Avatar fics]], the Fire Nationals use Agni in place of God ("Oh, Agni above..." "What in Agni's name?!").
* PapaWolf: When he sees Lu Ten get hit, Iroh takes out an entire legion of elite Earthbenders ''by himself.''
* ParentalNeglect: Ozai mentions that as a child, he was largely ignored by his father and older brother. However, Ozai is a fairly UnreliableNarrator, so it's debatable as to what degree this was true.
* PeacefulInDeath: Averted with Lu Ten. He dies in a lot of pain, afraid of what will happen to his loved ones without him, and thinking that he is ''not ready to die now at all.'' Iroh notes the distressed look on his face even after he dies.
* PiggybackCute: A decidedly non-shippy example - Lu Ten lets four-year-old Azula ride on his back on their way to the training field.
* PoisonedWeapons: Ozai gives Mongke and Vachir a Perfect Poison to use on their weapons to kill Lu Ten faster if the initial shots don't do it (which they don't, given that Lu Ten is MadeOfIron). It's implied that this poison is what Ursa (who Ozai stole the poison from) later uses to kill Azulon.
* RankUp: How was promoted from captain all the way to general for being able to kill Colonel Kei Rin.
* RedBaron: Lu Ten is known as the Sunstorm.
* RedSkyTakeWarning: The morning before the last battle at Ba Sing Se. Nageki even says, "Red sky, take warning, bloodshed by morning."
* SayMyName: ''"Uncle Ozai!"''
** ''"SHAN HOW!"''
** ''"LU TEN!"''
* ShootEverythingThatMoves: Iroh in his PapaWolf-rage-fueled ExtremeMeleeRevenge.
* SlasherSmile: Ozai in his GiveMyRegardsInTheNextWorld moment.
* SpareToTheThrone: Ozai is just the spare prince there in case something happens to Iroh, and he hates his status with a passion.
* StartOfDarkness: Azula has hers after her big cousin dies, and there is no one left to stop Ozai from doing whatever he wants with her.
* StealthInsult: Ozai saying goodbye to Lu Ten and Iroh is basically just him and Lu Ten taking shots at each other like this.
-->'''Lu Ten:''' ''(after Ozai mentions his requests to join them in battle being ignored)'' Well, Grandfather would know best, after all. Perhaps he sees that you would be of less use on the battlefield than you are here at the palace.
* SugarAndIcePersonality: Kei Rin, according to her son.
* SurvivorGuilt: Gisei gets this after [[spoiler: his friend Lu Ten dies protecting him.]]
* TakeUpMySword: Lu Ten's will instructed that [[spoiler: his dual dao swords]] be left to Zuko, and his entire collection of firebending scrolls be left to Azula, so that they can continue their training if he's not around to teach them.
* TakingTheBullet: [[spoiler: Lu Ten dies in a HeroicSacrifice like this, taking an Earthbender's boulder in the place of a young soldier he'd befriended.]]
* TalkingToTheDead: Chapter 3 opens with Lu Ten (mentally) doing this beside a portrait of his mother, telling her about everything he's seen and done in the Earth Kingdom.
* TearsOfRemorse: Iroh after Lu Ten dies in his arms. Like Azula, he believes it's all his fault for not being able to help him. They're both [[spoiler: wrong - if not for Ozai's little arrangement with Mongke and Vachir, Lu Ten would have been wounded, but not killed.]]
* TemptingFate: ''So much'' leading up to Lu Ten being killed. Lampshaded by the author.
** The best (worst?) examples are Iroh telling Lu Ten, "You shall see [the Fire Nation] again. We will return," on the ship to the Earth Kingdom, and the last line of Lu Ten's letter to Azula being, "With Agni's blessing, Dad and I will be back home with you guys before you know it."
* ThereIsNoKillLikeOverkill: The death of Lu Ten.
* TheyDiedBecauseOfYou: Azula blames Iroh for Lu Ten's death and tells him so. Combined with You Should Have Died Instead.
* TryingNotToCry: Lu Ten, Zuko, and Azula are all on the verge of tears as Lu Ten and Iroh board the ship to the Earth Kingdom, and all three are determined not to let them fall. [[ManlyTears Lu Ten is the only one who fails.]]
* TokenGoodTeammate: Lu Ten for the Fire Nation. He does believe in war, but not in racial dogma or the cruelty of Ozai.
* TheUnfavorite: Ozai. He believes that Azulon doesn't even consider him his son, due to his status as the SpareToTheThrone.
* UnwantedRescue: Gisei after [[spoiler: Lu Ten pulls his HeroicSacrifice, because he would rather have died himself than have his friend die in his place.]]
-->'''Gisei''': ''(in tears)'' Why would you do that, [[spoiler: Colonel?]] I didn't ask you to do that, not for me! What were you thinking?!
* WarriorPrince: Lu Ten and Iroh.
** Iroh's late wife Kei Rin was, by marriage, a warrior princess.
* WellIntentionedExtremist: Unlike the rest of the Fire Nation, Lu Ten does not think of the other nations as inferior races, believes there is a lot to learn from them, and wishes the Air Nomads hadn't been killed. However, he does believe that the war is necessary to make the world a better place.
* TheWisePrince: Lu Ten, like his father.
* WhyWontYouDie?: Mongke and Vachir both think this about the sheer amount of punishment Lu Ten is able to take before he finally dies.
* XMarksTheHero: Sometime before the siege of Ba Sing Se, Lu Ten gets a cross scar on his face. He notes specifically that the X shape was formed by a separate cut he got after the first had already been made.
* YouKilledMyMother: When Lu Ten sees General How - who trapped and killed his mother Kei Rin - among the Ba Sing Se forces, he charges right at him to confront him and says the trope name word for word. He fails to kill him, but apparently left a nasty scar across his chest.
* YouShouldHaveDiedInstead: Azula tells Iroh to his face that everyone would be better off if he were dead instead of Lu Ten.