r/WarhammerFanFiction • • Sep 27 '26

Question of the Week Question of the Week: What’s Your Favourite 40K Headcanon?

14 Upvotes

A headcanon is a fan's personal idea or belief about a fictional story that is not actually shown or confirmed in the original work. The Warhammer 40,000 universe is full of gaps, contradictions, unreliable narrators, and deliberately ambiguous lore which leaves plenty of room for headcanons.

So this week’s question is:

What is your favourite 40K headcanon?

It can be about anything in the setting. A character, faction, historical event, piece of lore, relationship, or even something you think makes the wider universe make more sense.

Maybe it's a small personal detail about a character, an explanation for a strange piece of lore, or a completely different interpretation of something Games Workshop has left deliberately vague.

Tell us your headcanon and, more importantly, why you believe it!


r/WarhammerFanFiction • • Oct 30 '25

Mod Announcement Welcome to r/WarhammerFanFiction — Read Before Posting!

15 Upvotes

Welcome, glad you’re here. This subreddit is a place to write, read, and discuss fanfiction set in Warhammer 40k, The Horus Heresy (30k), Age of Sigmar, and Warhammer Fantasy. Whether you’re forging grimdark epics or bright heroic tales, you’ve found the right place.

Before you post, the essentials

  • Flair is required. Choose one (Story, Prompt, Discussion, Essay, Misc, etc.) before submitting.
  • Use a universe tag in the title: [40k], [30k], [AoS], or [Fantasy]. Example: [40k] What happened to Logar? or [AoS] Where is Slaaneesh?
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  • AI content is not allowed. All fiction must be human-written.

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We host regular prompts, writing challenges, and feedback threads, check the pinned posts and the Events calendar (when available).

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Now, you introduce yourself below if you feel like it! Post a short intro or make a post about your latest work (with the proper flair and tag). We’re excited to read what you've written or read about!


r/WarhammerFanFiction • • 19h ago

Discussion [40K] Loken comes back wrong fanfiction idea

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16 Upvotes

As a last cruelty Samus bound Lokens soul and memories to his Gene Seed and left his body to rot, then Fabius Bail get's his hands on Lokens Body and experimented on his Gene Seed before putting it in a vat grown body Garvy was now half Luna Wolf half Thousand son. How would he deal with his return like that in 40K the Imperium has become everthing he tryed to prevent and is weaker than the Imperium he knew and Abaddon has spilt the Galaxy in half


r/WarhammerFanFiction • • 16h ago

Self-Promotion Rest Eterna - Mission Four | [40K] Bug Hunt campaign

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1 Upvotes

r/WarhammerFanFiction • • 19h ago

Self-Promotion The Codex Mundane: Act 1 complete (12 chapters). Guilliman wakes up in a German psych ward in 2026 [40K]

2 Upvotes

Hey all,

Since this is a sub about WH fanfic, I thought I’d post some.

I've just finished Act 1 of The Codex Mundane, a reverse-isekai take on Guilliman. He wakes up in 2026 on a German psychiatric ward as "Robert": no armour, no army, no Imperium, just non-slip socks and a lot of headaches.

I wanted the opposite of a power fantasy: a super-human who has lost everything and has to cope with the modern world one small thing at a time. It's dry, dark comedy that gets more serious as it goes, with a slow healing arc instead of a magic fix. No romance planned, and you don't need to know the lore.

Content note: mental illness, psychiatric medication and drugs, dissociation, severe depression and some graphic violence. Rated Mature.

Act 2 is in the outline phase. I'm new to fiction and English isn't my first language, so feedback is very welcome, especially on whether the "man, not monument" Guilliman feels true to you.

Read it here:

https://forums.spacebattles.com/threads/the-codex-mundane-guilliman’s-tactical-break-out-back-to-the-future-wh40k-au.1327897/

 https://archiveofourown.org/works/90408856


r/WarhammerFanFiction • • 1d ago

Discussion [30K] Could Loken be freed from Samus?

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4 Upvotes

Loken did not want to ascend to demonhood. Is there any hope for his soul to come back be it by controlling the Demon Prince or by splittering leaving a piece of Loken without the control of Chaos


r/WarhammerFanFiction • • 2d ago

Discussion [30K] Somehow Loken found himself in Westeros

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126 Upvotes

What faction would he join and how would he change the story? He starts in Winterfell at the beginning of season 1


r/WarhammerFanFiction • • 1d ago

Lore How does Gene Seed work? [40K]

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5 Upvotes

I am still new to 40K but I watched all episode of Space King


r/WarhammerFanFiction • • 1d ago

Discussion [30K] Somehow Loken found himself in the MCU

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9 Upvotes

How would the MCU change if Loken appeared in Avengers?


r/WarhammerFanFiction • • 2d ago

Discussion [40K] Are there anyother Halfbreeds?

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77 Upvotes

Honsu is a half Iron Warriors half Imperial Fist and I found that idea amazing just Imagine a half Space Wolf half thousand son


r/WarhammerFanFiction • • 1d ago

Other Do you want to see more content from my ultrakill x 40k crossover? [40K]

0 Upvotes

This is the basic lore of the crossover: https://www.reddit.com/r/Ultrakill/s/BwAU4cNHbi

12 votes, 1d left
Yes
No

r/WarhammerFanFiction • • 2d ago

Discussion [30K] Somehow Loken appeared in Star Trek

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10 Upvotes

What If Loken appeared on the Enterprise?

Instad of throwing a random 30K/40K charater into Star Trek Let's do this what if with Loken how would the Enterprise Crew deal with him? And How would he find this period in time?


r/WarhammerFanFiction • • 2d ago

Request [40K] a group of imperium rebels who ARENT genestealers/tau/chaos

6 Upvotes

Simply put I feel like whenever we see rebels in 40k, they are always secretly worse than the imperium somehow which I find extremely unlikely.

The imperium is so horrendously awful that every single citizen shouldn’t be blamed for wanting to overthrow it.

So how about a story of just regular rebels with (mostly) good intentions trying to overthrow a corrupt system that has only hurt them?

Obviously they are very unlikely to succeed but that doesn’t really matter for the story. I’m fine with a bad ending.


r/WarhammerFanFiction • • 2d ago

Lore [40K] Lore dos poke-marines parte 1: A chegada da Coalizão pele verde e a Campanha de Nanka

1 Upvotes

Bom dia, boa tarde e boa noite. Eu venho fazendo os poke-marines faz um tempo e eu agora estou tentando criar uma lore para eles esse é só um teste então me dem toques de onde posso melhorar ou de inconsistências que possam aparecer. Caso deseje conhecer os poke-marines basta olhar os posts no perfil

Campanha de Nanka

Nos sistemas Analius, Konarus e Nanka foram alertados sobre uma série de avanços de uma grande frota Orks em quantidades problemática, os Batedores que retornaram conseguiram notificar que essa frota foi fruto de uma incomum coalizão de clã estranhamente bem organizada. Os capítulos dos night moths enviando 600 astartes, Platinum guardians enviando 750 astartes e steel wasps com apenas 150 astartes foram acionados por ser o mais próximo do local para fortificar as forças de defesa da astro militarium no planeta Sistariu no sistema Nanka esse sistema e planeta em questão sendo uma área estratégica importante.

Contagem das tropas dos campos de batalha

Flanco esquerdo

Invasores da coalizão: Orks dos clãs Stikka-Tooth como vanguarda, Hard-Irun com tropas pesadas e DakkaBlast de cavalaria e suporte aéreo, todos liderados pelo Warboss que juntou os três Brokrar o devorador. Seus números chegando aos 10.000

Defensores imperiais: as tropas imperiais são os 300 astartes dos night moths como tropas de sabotagem, soldados do regimento de Nanka e do regimento Analius convocados para suporte no planeta sobre o comando local dos major de Nanka Morguns e major de Analius Ibadus do servindo como infantaria, o comando geral do lado esquerdo sendo do tenente Manbus dos Steel wasps e seus 49 marines totalizando o total de 6.000 mil tropas imperiais a esquerda.

Flanco direito

Invasores da coalizão:

Skrul-Thinka cavalaria pesada e vanguarda, Boss-Kriler unidades de investidas independentes e GrateKrumpas unidades de infantaria todos os três clãs liderados pelo Warboss Drukan, o mutilador totalizando 10.000 tropas

Defensores imperiais

Os 350 astartes dos Platinum guardians como principal linha de defesa liderados pelos capitães Hyor, Ganzus, Lopres e tenentes Vomus, Sergrio e Malbidos, dos regimentos Nanka liderado pelo major Xenkos e Analius pelo major Welion como tropas de defesa secundárias e com a liderança defensiva do tenente Lacron dos Steel wasps e seus 49 astartes totalizando 5.000 tropas

Campo de batalha central

Coalizão Ork

Liderados pelo Big Warboss de campo Krazibs, O predador a força principal invasora conta com os RedSplattar como infantaria, Grot-Slarve sendo sua cavalaria pesada, Big-Bita como unidades especiais e waag-sky como apoio aéreo totalizando 20.000

Defensores imperiais

Sobre as ordens do mestre do capítulo dos Steel wasps Mandarion e seus 49 astartes restantes estão 400 astartes dos Platinum guardians e 300 astartes dos night moths como defensores principais e o resto dos regimentos de Nanka e Analius com a liderança de campo do general Colucis de Nanka sendo um total de 15.000 mil

Esse grande palco é o que decide o destino de Nanka


r/WarhammerFanFiction • • 2d ago

Discussion Let's build a Timeline with different Franchises [40K]

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8 Upvotes

Star Trek > Dune > 30K > 40K What am I Missing?


r/WarhammerFanFiction • • 3d ago

Misc [40K] Saw an artist make some wonderful character profile templates and decided to fill one in for my party's Imperium Maledictium patron

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16 Upvotes

Thank you to u/skullivander for the lovely template! Would love to see more people's OCs


r/WarhammerFanFiction • • 2d ago

Prompt [40k] 2 inquisitors conduct a joint investigation on a chaos cult. They grow close and friendly. Until one finds out that his peer is...a Horusian.

1 Upvotes

r/WarhammerFanFiction • • 2d ago

Prompt [40k] A servitor who is providing ammo for the regiment experiences painful flashbacks: A soldier of the Militarum; A Tech Priest; an entity with lamps for eyes; searing pain; darkness.

1 Upvotes

r/WarhammerFanFiction • • 3d ago

Discussion [30K] A Primarch Crashlands on Westeros What faction would he join?

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94 Upvotes

r/WarhammerFanFiction • • 3d ago

Discussion [40K] Idea for an oc

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10 Upvotes

A Perpetual Space Marine who lost his mind early on in the great Cruesade and still thinks that he and his original squad are fighting in the great Cruesade


r/WarhammerFanFiction • • 3d ago

Prompt [40k] A Tau soldier falls in love at first sight with an Eldar, defects and tries (often failing) to help them and earn their love.

3 Upvotes

r/WarhammerFanFiction • • 3d ago

Misc [30K] Omegon and servitor Alpharius Part 2

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0 Upvotes

r/WarhammerFanFiction • • 3d ago

Looking For? [30K] I've read one or two "Big E raises the Primarchs" stories, would love to read some more?

4 Upvotes

I don't remember the exact titles of those I've read but I know one was quite high up on the list of 30K/40K fictions. It had all twenty Primarchs all raised by Big E from the start, learning of their psychic abilities, getting preventative measures to avoid falling, etc... A lot of it felt like the author's headcanon which I didn't mind too much.

Anyone got any recommendations for other stories with the same energy of a more brighter future for the Primarchs being possible?


r/WarhammerFanFiction • • 3d ago

Writing Help Writing help, [40k] [30k]

1 Upvotes

I have read istvaan 3 story so many times and find it tragic that the loyalists are forgotten so i had an idea to write a fanfic where istvaan 3 was secretly a Necron tomb world with a Phaeron or some such rank (am not very familiar with Necron rankings) witnessed everything that happened and either showed my homebrew chapter in 40k what happened or captured tarvitz and his surrounding loyalists during the final bombardment in one of those gadgets that Trazyn uses. Valid? Any tips? Did i flair correctly?


r/WarhammerFanFiction • • 3d ago

Misc [40K] Primarch 11 Ciaphas Cain Part 3

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6 Upvotes

Never post on r/sims4 they will ban you for a week instandly