Elden Ring is directed by Hidetaka Miyazaki, who penned the story alongside A Song of Ice and Fire author George R. R. Martin. Hidetaka has directed several games in the past, but he made his big break with the 2009 release of Demon's Souls on the PlayStation 3. This game established the beginnings of the Souls series and would be followed up with the multiplatform releases of Dark Souls in 2011, Dark Souls II in 2014, and Dark Souls III in 2016.
As an overarching franchise, both Demon's Souls and Dark Souls are known for their vast open worlds and dark medieval aesthetics. True to their names, the collection and usage of souls is an essential element. The worlds are usually set against a once-affluent kingdom that has fallen to ruin. Souls games also feature gameplay mechanics like the use of magic, weapon classes, and horrific boss enemies. Elden Ring features many characteristics of the Souls franchise. Does that make it a Souls game?
Not exactly. Elden Ring is its own intellectual property, according to its creator. In an interview with Weekly Famitsu (per Frontline JP), Hidetaka stated that the game and its narrative represent an evolution of the Dark Souls franchise. That basically confirms that Hidetaka wants this game to stand on its own, not beholden to the Souls series.
This wouldn't be the first time he would do this with his games. Other popular titles from Hidetaka like Bloodborne and Sekiro: Shadows Die Twice also share gameplay elements with the Souls franchise while existing as their own individual worlds. Hidetaka's usual game design has even spawned its own unofficial subgenre in gaming that some call "Soulsborne" games.