Sung "Flawless" Yeon-jun (Hangul: 성연준) is a jungler for Rogue Warriors. He was previously known as Flaw.
Sung "Flaw" Yeon-jun joined SBENU Sonicboom as a substitute jungler during SBENU Champions Summer 2015. SBENU placed last in SBENU Champions Summer 2015 and were forced to play in the LCK 2016 Season Spring Promotion. SBENU played Ever and managed to win 3-1 to requalify for the LCK, marking Flaw's first competitive games.
SBENU played in the 2015 LoL KeSPA Cup where they lost 2-1 in the quarterfinals to SK Telecom T1.
During the 2016 LCK Spring Season, SBENU Sonicboom went 2-16 in sets, finishing in ninth place, forcing them to play relegations matches for their spot in the summer split. SBENU chose ESC Ever as their relegations opponent, but were defeated 3-0, relegating them to Challengers Korea 2016 Summer.