The lead singer and primary songwriter of the band is known by the moniker "Vessel". Vessel and II are the only members of the band who have been credited as performers on Sleep Token's studio albums. II is also the only member apart from Vessel who has been given songwriting credits.
The group's focus on anonymity and visual style have been likened to similar practices employed by
Ghost,
Slipknot, and
Gwar. Slipknot's frontman
Corey Taylor has praised the band's image and artistry, comparing their approach to the one Slipknot took in the band's early days.
In 2017, Sleep Token's then-new label
Basick Records published a description of the band which read, "A band that goes above and beyond simply writing and playing music, Sleep Token are said to be "the mortal representatives of the ancient deity known only as 'Sleep', led by the masked and cloaked figure appointed 'Vessel' ... the master creator behind the music."