The Korean music industry was struck with some very sad news on October 8 that one of K-Pop's most beloved singers, Rottyful Sky, had passed away due to complications with a brain tumor at the young age of 25.

Rottyful Sky, whose real name was Kim Hanul, made her debut in 2001 as Hanul at just 13 years old with the album Voice of Purity and instantly won over the hearts of fans around Korea.

A young girl with a powerful voice, Hanul paved the way for today's soulful youngsters Lee Hi and 15&, among others.

Her first title track "Utgine" showed off her vocal talents and opened doors, leading to a successful music career nearly a decade later.

The song is a rough cover of the 1969 Shocking Blue hit "Venus" (later revamped by 80's pop-rockers Bananarama) and has a playful sound.

Voice of Purity was her only release as Hanul before changing her name and making a solo comeback nine years later as Rottyful Sky with the single "No Way." In the middle, Kim Hanul had some minor success with hip-hop dance group Roo'ra and as a member of another group by the name of MADmoiselle.

Despite not having the same name recognition in the industry as many other leading K-Pop vocalists, over the last several years Rottyful Sky developed a very strong fanbase among her entertainment industry peers.

With the recent sad news of her illness and death, K-Pop stars from Rain to Big Bang's Taeyang to Rainbow member Yoonhye and many more have expressed their condolences and paid their respects to the late singer, proving that her influence was not only far reaching, but will also be greatly missed.

Rest in peace, Rottyful Sky - and thank you for you contribution to K-Pop over the past 12 years.