Fics like Three's Company

We stumbled over this lovely little thing, and things got a bit out of hand. Chapters are -not- necessarily in a chronological order, nor are they supposed to be. "So instead of being driven by a desire for vengeance, Ardyn just sort of breaks, goes crazy in an entirely different direction and spends the several centuries wandering around as a crazy homeless man until mental institutions become a thing, he gets institutionalized in Niflheim and instantly becomes the subject of early scientific scrutiny until a mad military scientist gets the brilliant idea to use him to turn people into scourge-based weapons. Lucis, fearing Nifleheim's new weapons, sends Cor to investigate these new weapons and he ends up coming back with a mentally ill immortal and a baby, and yes he's keeping them."

You may also like

The Loveless Prince by NiuNiu (Final Fantasy XV)
Deep in the Dark by orphan_account (Final Fantasy XV)
Vox Deorum by strikedawn (Final Fantasy XV)
golden catfish, king catfish by unsungillumination (Final Fantasy XV)
Caring for Sick Royalty: A Survival Guide by LuckyLectio (Final Fantasy XV)
Oh, You Wondrous Creature by Ginia (Final Fantasy XV)
Little Closer, Close Enough by surveycorpsjean (Final Fantasy XV)
it's not having what you want (it's wanting what you've got) by element78 (Final Fantasy XV)
The Last Prince of Tenebrae by ohmyfae (Final Fantasy XV)
friends with benefits by brosura (Final Fantasy XV)
Civil Hands by Crazyloststar, chasingfigments (Final Fantasy XV)
Close Quarters by dirtbagtrashcat (Final Fantasy XV)
The Great Live Stream Debacle by Choke-a-Bro (Final Fantasy XV)
Divenire by countingpaperstars (Final Fantasy XV)
my address is your name by dustofwarfare (Final Fantasy XV)
Best Foot Foward (one step back) by PushPin (Final Fantasy XV)
cause you’re fine and you’re mine and you look so divine by taizi (Final Fantasy XV)
The Arcade by Gnine (Final Fantasy XV)
Introductions by doodly_squat (Final Fantasy XV)
A Real Charmer by ohmyfae (Final Fantasy XV)