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1. Investigating The Dark Abyss (A DainsLumi Modern AU Fanfiction) by sabis_fanfictions

   Fandoms: 原神 | Genshin Impact (Video Game)  

   • Mature
   • Creator Chose Not To Use Archive Warnings
   • F/M
   • Work in Progress

   31 Oct 2025

   Tags

   • Creator Chose Not To Use Archive Warnings
   • Dainsleif/Ying | Lumine (Genshin Impact)
   • Kong | Aether & Ying | Lumine (Genshin Impact)
   • Teppei/Ying | Lumine (Genshin Impact)
   • Minor or Background Relationship(s)
   • Dainsleif (Genshin Impact)
   • Ying | Lumine (Genshin Impact)
   • The Abyss (Genshin Impact)
   • The Abyss Order As The Mafia
   • Abyss Ying | Lumine (Genshin Impact)
   • Abyss Kong | Aether (Genshin Impact)
   • Lumine and Aether Both Have Their Abyss Sibling Personality But Not Much of Their Traveler Personality
   • mafia
   • Mafia Boss Ying | Lumine (Genshin Impact)
   • Technically Mafia Boss Candidate Along With Aether
   • Mafia Boss Kong | Aether (Genshin Impact)
   • Sibling Rivalry
   • Sibling Love
   • Action/Adventure
   • Drama & Romance
   • Murder Mystery
   • Courtroom Drama Based On Ace Attorney Sorry If My Logic Sucks
   • Modern Teyvat (Genshin Impact)
   • Alternate Universe - Different First Meeting
   • Alternate Universe - Assassins & Hitmen
   • Alternate Universe - Thieves
   • Alternate Universe - Bounty Hunters
   • Alternate Universe - Royalty
   • FBI
   • Organization Inspired By The Illuminati and The Court of Owls (DC)
   • Military Backstory
   • Military Inaccuracies
   • Lieutenant Dainsleif (Genshin Impact)
   • FBI Agent Dainsleif (Genshin Impact)
   • Dainsleif-centric (Genshin Impact)
   • Character POV May Change but It's Mostly Dainsleif POV
   • POV Third Person Omniscient
   • Homunculus and Clones
   • Ensemble Cast
   • Age Difference
   • Older Woman/Younger Man
   • Slow Burn
   • Slow Build
   • Slow Dancing
   • Enemies to Lovers
   • Enemies to Lovers but They Hate Each Other at Different Points in the Story
   • Enemies Forced To Work Together
   • Forced Proximity
   • Angst
   • Hurt No Comfort
   • Questionable Ending
   • Survivor Guilt
   • Mental Health Issues
   • Mentioned Halfdan (Genshin Impact)
   • Morally Ambiguous Character
   • some smut and romance but mostly plot
   • Doomed Relationship
   • Fake/Pretend Relationship
   • Temporary Fake Dating
   • Unresolved Tension
   • Grief/Mourning
   • References to Alcohol
   • references to history
   • References to Other Series But Not a Crossover
   • some characters have the same or similar backstories to the canon storyline or lore with minor differences and twists
   • different from the canon storyline because some parts of the Genshin plot line are wack like wdym there are spaceships now
   • some similarities to the game's plot line but modernized and Dainsleif is the protagonist
   • Other Ships Not Mentioned in Tags
   • One-sided Love Triangle with Dainsleif/Lumine/Lyney
   • Implied Semi-Problematic Ships or Pairings with Aether
   • Teppei will appear later in the story but you might wish he didn't
   • Triggers
   • Song Lyrics
   • Blue Topaz - Freeform
   • Moon and Beloved of The Moon

   Summary

   Dainsleif Rudava is renown as one of the most successful and reliable military commanders in all of Teyvat. Joining the military at just 17, Dainsleif was a prodigy in both gunfire and sword fighting. Naturally, he earned respect throughout his career and eventually climbed up the ranks to become a military lieutenant. His name remains as a legend throughout Teyvat as the "Twilight Sword".

   However, when his best friend Halfdan, who works for the FBI, goes missing, Dainsleif is determined to find answers as to what happened to him. The FBI believes that maybe the Dark Abyss, a powerful mafia group, has either taken him captive or silence him permanently.

   Either way Dainsleif is determined to find answers, even if that means throwing everything away:
   his career, reputation, and even his own name

   But there's one problem, he's not the only one looking for answers.

   (READ THE NOTES FOR THE OTHER UNTAGGED SHIPS OR RELATIONSHIPS BECAUSE I COULD NOT FIT ALL OF THEM)

   Trigger Warnings (TW) will also be listed and bolded at the beginning of the chapter if any apply for that specific chapter!

   Language:

   English

   Words:

   21,664

   Chapters:

   6/?

   Comments:

   7

   Kudos:

   14

   Bookmarks:

   4

   Hits:

   243