Isaac, Maggie, Judas, Cain, Eden: Basically the same concepts as in Epiphany, but with different looks.
Azazel: The only one here who isn't my design, it is instead "tainted tainted azazel" from the one guy on the tboi subreddit because i couldn't think of anything myself.
Eve: Her getting choked by the serpent
Samson: Him being blind, pissed, and chained to the stone pillar, I imagine he'd attack with it in some fashion.
Blue Baby: He shat his guts out, painted himself in shit, and now uses his intestines as a "lasso" of sorts. He drags enemies into piles of shit and they die.
Forgotten: He takes damage with every attack he lands, but his attack overall is much stronger and can spin around him if charged.
The Lost: Isaac's immortal soul. He gets a couple of items at the start of the run and can only get more through angel deals. Any other items get turned into coins or soul hearts. His stats are kinda shitty to make up for his strength and higher health. Starts with 3 soul hearts.
Lazarus: Laz and dead Laz stitched together, dubbed "Schrödinger's Laz".
Apollyon: More Void. It's leaking. Run.
Beth: Statue made of her own psychic stone stuff. Uses phychic tears, very fragile, moves like Edith.
Lillith: Way, way too full of children. Probably really slow but has her children attack a lot more.
Keeper: The cloth on his neck fell off, exposing the rotting body underneath. Probably gets money by taking damage or smth i dunno.
Jacob and Esau: They made up, like in the original story, and do everything together. Move, get items, and share a healthbar. Basically, they don't suck now, and are now OP! :D