From either survivor or killer. Mine would probably be Clown, I feel like his backstory was well thought out and had a lot of detail.
The plagues was pretty good, as well as the Huntress
Nurse's, although its not because of her bio on the info screen. Every single one of her addons tells a mini story that fleshes out her backstory, the people she interacted with and gives little bits and pieces of what her life was like. It reminds me of Dark Souls where the majority of what you learn about the world is in item descriptions.
Gee, for survivors maybe I'd go with that TV presenter person. Idk what it was, but something about her story made me sad.
Also literally everything @PeepingPeacock said.
The Nurse is one of the most ghost-like characters in the way her story is told. Her bio reads like a campfire story, the offerings and perks all fit that theme, too. I can imagine a bunch of people sitting around a campfire, right near an abandoned asylum, telling the story of poor Sally Smithson, the widowed nurse who went mad and killed everyone before fleeing. It FEELS right to me I guess.
I don't know how to behave in the forum's yet so I'm sorry for tagging if tagging is frowned upon
For Survivor: Ace. He's the only survivor who is happy to be in the Trials.
There's a handful of killers like that, but no other survivors.
Killer is a tougher question as they're all pretty good. I really like that Mikey just walked in like he owned the place. I also love how super chill Ghostface is.
From a good story perspective I'd say it's the "Did nothing wrong club" Spirit, Wraith, Huntress, Hag, Plague, etc. The killers who were hurt more than they harmed, excluding Huntress who literally couldn't comprehend empathy due to how feral she was from living alone in the forest after watching her mother die a slow brutal death.
Really liked plagues back story, She is also by far the oldest killer in the game. She has awesome Babylonian roots in her story so yea she is cool also the clowns story is pretty cool
Huntress and Nurse. It's a shame Nurses busted power overshadows her lore and design because she's one of the more disturbing killers in the game.
My two favorites are funnily enough from the same chapter: David Ling and the Huntress.
Clown I like the best because it's just a creepy story.
Spirit's pretty great because of the twist of it and made me go "oooooh!"
That was quite hard to pick out because I pretty much like all of them.
Ace. If you really think about it, you can do a lot of theorizing based off of the little amount of lore we got from him ranging from how he could have got there to if he knows how the realms work. Possibly one of the most overlooked characters too.