Fics like don't swear to god (he never asked you)

No one joins him. Not Allura. Not Shiro. Keith looks into the emptiness of space and only sees himself. He sees the endless black and wishes it would come for him, tear out his throat, take his sorrow with it. No one was meant to hold this much grief within them. In which Shiro and Keith heal their friendship, the Paladins work through their grief, and they all find their way back to each other. PIcks up right after when they say goodbye to Allura in Season 8. Not epilogue-compliant.

You may also like

Spun like Sugar by Neyasochi (Voltron: Legendary Defender)
If You're Gasoline, I'm Matchsticks by an_aphorism (Voltron: Legendary Defender)
thread our way through a string of stars by orphan_account (Voltron: Legendary Defender)
nothing can breathe in space by idrilka (Voltron: Legendary Defender)
Shiro the Hero and the Hungry Chain by Saasan (Voltron: Legendary Defender)
who in the world is keith's husband? by ailurea (Voltron: Legendary Defender)
Balancing Act by an_aphorism (Voltron: Legendary Defender)
Project Zero by TruebornAlpha (Voltron: Legendary Defender)
Tip Jar by jubilee_jawz, maireeps (Voltron: Legendary Defender)
Guy(s) like you should wear a warning by warschach (Voltron: Legendary Defender)
'Shiro and Keith's Kickass Fighting Techniques' by Lance McClain by skyestiel (Voltron: Legendary Defender)
Between the Shadow and the Soul by magisterpavus (Voltron: Legendary Defender)
heartbreak prevention for dummies by ailurea (Voltron: Legendary Defender)
one way ticket to another life by starboykeith (Voltron: Legendary Defender)
trust is a mobius strip by sinspiration (Voltron: Legendary Defender)
The Shape of Knowing You by Sleepy_existence (Voltron: Legendary Defender)
The Cause and Cure (Is You) by SeventhStrife (Voltron: Legendary Defender)
Cinderfella by GoldenTruth813 (Voltron: Legendary Defender)
Wild Card by arcadenemesis (Voltron: Legendary Defender)
The End is the Beginning by magisterpavus (Voltron: Legendary Defender)