Due to the changes to the OGN rules, Sword and Shield were forced to merge, forming NaJin e-mFire. Shield's top laner, Save, departed from the organization, giving Duke sole possession of the starting position. The team was invited to SBENU Champions Spring 2015 where they placed 6th in the regular season and missed the playoffs. Despite his team's mediocre performance, Duke earned the MVP award for the season. NaJin placed fifth in the regular season of SBENU Champions Summer 2015 and qualified for the playoffs but they lost in the first round 2-1 to the KOO Tigers. They earned enough circuit points to make it to the 2015 Season Korea Regional Finals but lost 3-0 in the first round to the Jin Air Green Wings.
NaJin played in the 2015 LoL KeSPA Cup where they lost 2-1 to Rebels Anarchy in the first round. Duke left NaJin in December and joined SK Telecom. In March, SK Telecom attended IEM Katowice despite being only the sixth-place LCK team at the time. They brought substitute jungler Blank in place of bengi and swept through the tournament, winning the title after only seven games. After their international success, they returned to Korea and placed third in the regular season, earning themselves a spot in the playoffs. SKT won the playoffs, winning their third championship in a row and for the first time a seed to the 2016 Mid-Season Invitational.