During his various incarnations:
- As the Aesir leader Niord, he led his people southwards, into Pictland, defeated then befriended the Picts, killed Satha the Great Serpent (Set), and avenged his people by slaing the Worm. That tale, seemingly set in the end of the Hyborian Age, was allegedly the basis for tales such as Perseus and the "mammoth sea-born serpent", Beowulf and his "fearsome fire-monster", Saint George and his dragon, or Siegfried and Fafnir.
- He followed Brennus during the sack of Rome.
- He sacked plantations and villas along with Alaric and his Goths.
- He was among the Crusaders led by Godfrey of Bouillon, attacking Jerusalem.
- Another one of his spirit ancestors was buried in a mausoleum in Dunbar Castle, Northumberland (England), and was targeted by cultists of Set in 1584, but was defended by Solomon Kane. This body was used by James Allison from 1936 to communicate with Solomon Kane (who severed the head, thinking he was witnessing the rising of the dead) and the time-displaced Moon Knight, urging them to join him in quest to foil Set's plans.
As the Wyrm achieved his schemes using Allison, Conan, Agnes, Solomon Kane, and Moon Knight, he briefly revealed his intent, then left James Allison for Hyborian Age's Stygia. Allison immediately recovered his full mind, and the extent of his mistake.
During his last moments of life, agonizing in his deathbed, Allison relived his confrontation with the monsters of the Valley of the Worm in one of his reincarnations, that of the barbaric Niord.
As he was dying, he was able to see his previous incarnations' lives.
- James Allison was created by Robert E. Howard in the short story "The Valley of the Worm" (Weird Tales; February, 1934) adapted in Marvel Comics by Roy Thomas, Gerry Conway, and Gil Kane, in Supernatural Thrillers #3 (April, 1973).
- In Conan: Serpent War #1, James Allison lived in Cross Plains, Texas, and was dying in 1936, the hometown and year of death of Robert E. Howard.
- No other stories (and past lives) or James Allison have been adapted by Marvel Comics so far. The second and only other story published during Howard's lifetime, "The Garden of Fear" (July-August 1934), was published in Marvel Tales, a short-lived fantasy/science fiction magazines. The title was reprised by another short-lived fantasy/science fiction magazine, itself reprised by Timely Comics (Marvel Comics' first iteration) for the rebranding of Marvel Mystery Comics in August, 1949.
- 4 appearance(s) of James Allison (Earth-616)
- 1 minor appearance(s) of James Allison (Earth-616)
- 1 image(s) of James Allison (Earth-616)
- 4 quotation(s) by or about James Allison (Earth-616)