Kang "Blank" Sun-gu joined Energy Pacemaker.Carries in December of 2014. EPC played in the 2015 Demacia Cup/Spring Season where they placed 17th-28th after losing 3-0 to Team King. They then participated in the 2015 LSPL Spring Season but only placed third in their group and were forced to play in the 2015 LSPL Summer Relegation Tournament. Here, EPC managed to requalify for the LSPL with 2-0 victories over Team DK and Stand Point Gaming. Blank left EPC to join Star Horn Royal Club as a jungler in May of 2015. His first professional games were as a sub for inSec during his injury in the LPL Spring Season. Royal ended in tenth place and were eventually relegated. His only other games were in the 2015 Demacia Cup Summer Season where Royal lost 3-0 to Snake eSports in the second round.
Blank left SHRC in December to join SK Telecom T1 as a jungler. In the LCK first round robin, SKT ran bengi as their starting jungler, and Blank played only four games with a 1-3 record. He made his international debut at IEM Katowice in March, when the team brought him instead of bengi to compete. SK Telecom swept the event, winning in only seven games. Blank's performance improved in the second round robin where he became the team's starting jungler, helping SKT achieve third place in the regular season. During the playoffs, SKT placed first, winning their third championship in a row and giving them a seed to the 2016 Mid-Season Invitational.
Their first place finish in the spring season earned them a spot in the 2016 Mid-Season Invitational. Notably, SK Telecom T1 were the only team to return to 2016 MSI from 2015 MSI. As the reigning domestic champions of Korea, SK Telecom T1 came into the tournament as massive favorites to win. However, their group stage performances were very lackluster as they dropped games to China's Royal Never Give Up, NA's Counter Logic Gaming, and two games to the LMS Flash Wolves. They ended their group stage with a 6-4 record, seeding them into the bracket stage at fourth place. Matched up against Royal Never Give Up in the semifinals, SK Telecom started to regain their form, beating them 3-1. They then proceeded to beat Counter Logic Gaming 3-0 to win the event and give them the trophy that barely escaped them last year.
During the 2016 LCK Summer Split, SKT started to play longtime starter Bengi once again, and Blank shared the starting spot. SK Telecom started the season strong with a 5-0 score in series and 10-0 game score. However, they started dropping sets to lower ranked teams, notably the Afreeca Freecs, who they failed to win even a single game against the entire season. With a 13-5 scoreline in series, SKT placed second in the round robin, beating KT Rolster via game score tiebreaker. However, during the 2016 LCK Summer Playoffs, they met KT Rolster in the semifinals, where they were reverse swept 3-2 after going up 2-0 in the first two games. This gave them third place for the summer split. Combined with their first place spring finish, as well as the victory of the ROX Tigers over KT Rolster, SKT qualified to the 2016 Season World Championship on points as Korea's second seed.
At the 2016 Season World Championship, SK Telecom T1 were placed into Group B, along with LMS's Flash Wolves, NA's Cloud 9, and China's I May.