The classic d100 investigative system from Chaosium .

is a celebrated cinematic roleplaying setting that merges the terrifying cosmic horror of H.P. Lovecraft’s Cthulhu Mythos with the historical backdrop of World War II. Originally launched by Modiphius Entertainment, the game invites players to fight a "Secret War" against Nazi occultists and ancient, malevolent entities. The Premise: The Secret War

A narrative-focused system that prioritizes storytelling over complex math. Essential PDF Resources