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1. Project Sentry by TheRaven1

   Fandoms: Thunderbolts (Movie 2025), Marvel Cinematic Universe  

   • Not Rated
   • Creator Chose Not To Use Archive Warnings
   • Other
   • Complete Work

   20 Oct 2025

   Tags

   • Creator Chose Not To Use Archive Warnings
   • Yelena Belova/Ava Starr
   • Valentina Allegra de Fontaine
   • Yelena Belova
   • James "Bucky" Barnes
   • John Walker (Marvel)
   • Ava Starr
   • Mel (Thunderbolts 2025)
   • Alexei Shostakov
   • Antonia Dreykov
   • Robert "Bob" Reynolds (Marvel)
   • Alternate Universe
   • Depression
   • mental health
   • Angst
   • What if Yelena went through the Sentry Project
   • spoiler alert: it doesn’t go very well
   • I’ll be adding tags as I go
   • I’ll be adding characters as I go
   • Poor Mel needs a vacation
   • Yelena Belova Needs a Hug
   • Everyone Needs A Hug
   • Yelena Belova Has Issues
   • POV changes regularly
   • Mentions of Suicide
   • Yelena as Sentry
   • The Void
   • Ava Starr Needs a Hug
   • Bucky keeping everything together
   • Rare moments of fluff
   • Wasn’t going to add romance but the muse demanded it
   • slow burn?
   • romance is not the main focus
   • Bob is just a regular guy
   • Kinda
   • Bob and Yelena are platonic soulmates
   • Ava and Yelena are romantic ones
   • Yelena Belova and Robert "Bob" Reynolds are Like Siblings
   • Walker starts off as an asshole but ends up being a good person
   • As does Antonia
   • Sentry!Yelena
   • I’ve realized that I’ve been using “a million suns” instead of “a thousand suns”
   • But whatever. We’re just gonna roll with it
   • shame rooms
   • Emotional Hurt/Comfort
   • I swear I don’t hate Natasha Romanoff
   • Protective Yelena Belova
   • It’s also now O.X.E. Corp not O.X.E. Group in this fic lol
   • Just please ignore any typos
   • Author doesn’t know how to type to save her life
   • Ava: gets hurt
   • Yelena: “THE RIVERS WILL RUN RED”
   • Earth 525

   Summary

   With legal troubles looming on the horizon and reports of her…experiments failing, Valentina Allegra de Fontaine is definitely having a very bad day.

   It doesn’t get better when her (probably crazy) shadow-ops agent Yelena Belova signs up for the top-secret Sentry Project with absolutely no idea what she’s getting into.

   But it’s okay. No one’s survived it before. To Val, it’s a quick way to get rid of a wild card that refuses to listen to directions.

   But obviously, knowing her luck, it wouldn’t be that easy.

   (What if…Yelena Belova became the Sentry instead of Bob Reynolds?)

   (WARNING: Swearing, mentions of suicide, child abuse. I do post warnings before chapters that may trigger you, but be careful and take care of yourself!)

   Series

   • Part 1 of Golden Like A Firefly

   Language:

   English

   Words:

   58,611

   Chapters:

   24/24

   Comments:

   250

   Kudos:

   117

   Bookmarks:

   18

   Hits:

   2,633