One of a Kind is the ninth extended play by the South Korean boy group Monsta X.

[3] On May 3, Starship Entertainment announced that Shownu would not be promoting with the group for the comeback due to health issues.

[5] Ruby C, writing for NME, describes "Gambler" as a departure "from the group's usual (and predictable) title-as-a-repetitive-hook formula to create an alluring and unadulteratedly fun song".

For the track "Secrets", she also wrote that, "it could have fit right in with [All About Luv's] pop sensibilities, sax outro, and mildly suggestive lyrics".

[6] The EP peaked at number three on the weekly Gaon Album Chart and sold more than 300,000 copies in its first month of release in South Korea.