Since it initially premiered on The CW in 2005, Supernatural has enjoyed long-lasting success, with it largely considered the most popular series for the network as well as The CW's best show of all time. Across 15 seasons of Supernatural, fans were blessed with the spooky escapades of the Winchester brothers, as they battled everything from grounded monsters to biblical entities along the way. Despite its immense staying power from the beginning, Supernatural never really became a massive universe for The CW, akin to something like the sprawling Arrowverse or The Vampire Diaries' substantial spinoff shows.