Snorri Sturluson

Snorri Sturluson was an Icelandic politician who was elected twice as lawspeaker to the Icelandic parliament, the Althing. He is commonly thought to have authored or compiled portions of the Prose Edda. He was assassinated in 1241. Snori mixed Christian concepts and parallels into traditional Norse mythologies.

Creationism
The account of the “heathen” Norse creation narrative comes from the works of Snorri.

Niflheim
The word “Niflheim” is only found in the works of Snorri who gave a poetic embellishment of Hel. “Niflhel” is found in Old Norse poems that are much older than Snorri’s works. It’s entirely possible that the word “Niflheim” is an invention of Snorri.