MONSTA X member Ki Hyun is making a solo comeback after approximately 3 years and 9 months. On the 7th at 6 PM, Ki Hyun will release the complete tracks of his mini album 'BORDERLINE' and the music video for the title track 'So Good' through various music streaming platforms. The new album contains Ki Hyun's journey of discovering and pursuing his own path rather than a predetermined one, consisting of a total of 7 tracks. The title track 'So Good' features an escalating guitar sound and explosive vocals, capturing the moment of deciding to trust one's own senses and choices amid a world that forces predetermined answers. In an interview, Ki Hyun revealed that after military service, he has "changed so much that he has become almost a different person as he entered his late 20s and 30s," reflecting that he was previously confined by a narrow perspective. He cited rock music as the catalyst for change, saying "rock music opened me up like a digestive aid that cleared my insides." He also emphasized avoiding musical picky eating, explaining "I intentionally tried not to lose ballads and lyrical elements to prevent being too focused on rock alone." Regarding his ultimate goal as a vocalist, he stated "My goal is to reach the level of skill where my songs shine the brightest when I sing them, something that no one else can take away."