크루셜스타(Crucial Star)，原名为朴世允，1989年10月16日出生于韩国首尔，韩国的hiphop音乐人。以歌手，RAPPER和制作人的身份进行活动。Soul Company的面试合格后，以Soul Company的艺人身份进行活动。2011年Soul Company解散后，加入了Grandline Entertainment。2012年发表专辑《FALL》。现为C-JeS Entertainment旗下艺人。 Park Se-yoon (Hangul: 박세윤), more commonly known as Crucial Star (Hangul: 크루셜 스타), is a South Korean rapper, singer-songwriter, and producer currently signed to C-JeS Entertainment. He began his career at the age of 17, as a member of the hip hop group Libra Twins. Park Se-yoon was born on October 16, 1989 in Seoul, South Korea. His father is the painter Hang-Ryul Park. He made his musical debut at the age of seventeen in the hip hop group Libra Twins. Several years later, he signed with independent hip hop label Soul Company, working under the name Crucial Star. He and label mate Mad Clown collaborated on the digital album Mad Clown VS Crucial Star in 2010. The following year, he released his first EP, A Star Goes Up, and his first full-length album, A Star From The Basement. Following the dissolution of Soul Company in 2012, Crucial Star moved to Grandline Entertainment.While with Grandline, he released two mix tapes, Drawing #1: A Dream Spokesman (2012) and Drawing 2: A Better Man (2013), two albums, FALL (2012) and Midnight (2014), and one EP, Boyhood (2015). In 2015 he appeared as a contestant on Mnet television rap contest Show Me the Money 4. He was eliminated in the preliminary round after forgetting his lyrics.In October 2015, Crucial Star's agency C-JeS Entertainment published a statement announcing that he and Unpretty Rapstar 2 contestant Heize were in a relationship. A week after this announcement, it was reported that they had broken up several months prior. He left Grandline Entertainment in January 2016 when his contract ended. In April, he signed with C-JeS Entertainment.