Obviously this isn't going to be a complete character list, cause… spoilers, but it will grow as more characters are introduced in future chapters.
Main(s):
These are the characters that will frequently appear in ever chapter.
Joe/Jörmungander: Original name Henry Everett. Self Aware of being an absolute unit and a Gary Stu. Also can't name things for shit. Has become the Biblical God due to his obscene luck and because 'haha funnies'.
Gabriel: Seraph, and Gods number one fan. Seems a bit ditzy at first but is actually 'haha funnies' level OP.
Ophis: The Infinite Dragon Loli. In this AU, she is Gods sister. Strange fascination with violating enemies with her snakes, also likes teeth rotting amounts of sweets.
Supporting:
Salazar Slytherin: Joe's adoptive father after he gets Isekaied. One of Hogwarts' four founders. Not a racist, spent some time as a ghost after his death, is currently a Seraph in training. Has a petty vindictive side.
Rowena Ravenclaw: Salazar's main squeeze, also another of the founders. Joe's adoptive mother. Spent some time as a ghost with Salazar, also currently a Seraph in training.
Godric Gryffindor: Burly, Scottish, and 100% a battle maniac. One of the four founders Has a secret soft side, terrified of Helga. Currently training as a Seraph after being revived by Joe.
Helga Hufflepuff: Secretly Joe's favourite founder since she's doesn't call him by his full name (Jörmungandr). One of the four founders, currently training to be a Seraph. Has Godric by the short and curlies.
Helena: Helena Ravenclaw, Joe's adoptive sister, never became the Gray Lady due to AU and Joe's interference. Unofficial secretary, really annoyed at Joe, currently a ghost haunting Slytherin's property.
Freya: The second basilisk in the Chamber of Secrets since the first one became the MC. Sleeps a lot… loathes the name 'Tom'. Currently loitering in the CoS.
Nicolas Flamel: Kooky old alchemist, inventor of the Philosopher's Stone. One of Joe's first friends outside of the founders. Currently galavanting through France.
Perenelle Flamel: Nicolas' wife and carer. Currently watching her husband galavant through France making sure he doesn't set himself or the country on fire.
Vlad Tepes: Vampire Lord, actually just a hopeless romantic. Joe's blood brother.
Mina Murray: Reincarnation of Vlad's wife. Eventually remembers her past life.
Tony Stark: Ironman, self proclaimed playboy philanthropist. Doesn't die.
Steve Rogers: Captain America, Boy Scout, doesn't beat up a crippled billionaire with his war buddy.
Bruce Banner: Green.
Clint Barton: Legolas, bow and arrow guy. Secretly a fan of Joe.
Natasha Romanov: Sexy redheaded spy lady.
Yelena Belova: Sexy redheaded spy lady's sister and also a sexy blonde assassin. Potential ménage à trios recruit.
Thalia Grace: Former demigod daughter of Zeus, currently an Angel training under Yelena and Natasha.
Uzumaki Kushina: Jinchuriki of the Kyuubi no Yoko. Former student/apprentice of Joe/Akimitsu. Currently engaged to Joe/Akimitsu bestfriends with Mikoto.
Uchiha Mikoto: Kushina's bestfriend, daughter of the former Uchiha clan head. In a relationship with Minato.
Namikaze Minato: Jiraya's apprentice, candidate for the position of Hokage after Hiruzen.
Great Red/Ruby: Sister to the MC and Ophis. Dragon God of Dreams. Her human form is that of a busty red haired woman with scales covering parts of her body. She not so secretly has a crush on her brother.