Pessimist has been a regular guest, first appearing on 8 December 2016 and most recently on 9 September 2017. Pessimist has been played over 130 times on NTS, first on 17 April 2016. Pessimist's music has been featured on 124 episodes.

Kristian Jabs, also known as Pessimist, aged 20 is a Drum & Bass Producer/DJ from Bristol. He has been producing since the age of 15 and has recently become one of the scenes most prolific newcomers of the underground. A distinct style and not conforming to predictable trends has earned Pessimist a respectful reputation in Drum & Bass.