Question: is demon's souls part of dark souls

Answer: Yes, The Souls series (ソウルシリーズ, Sōru shirīzu) is a series of action role-playing video games created and developed by FromSoftware. The series began with the release of Demon's Souls for the PlayStation 3 in 2009. It was followed by Dark Souls in 2011, and its sequels, Dark Souls II and Dark Souls III, in 2014 and 2016, respectively. The series' creator was Hidetaka Miyazaki, who directed all of them with the exception of Dark Souls II.