Heo "Huni" Seung-hoon started his League of Legends career as a part of the Samsung organization as a practice partner for the team, though he was never officially a substitute for the team.
The first team Huni officially joined was Fnatic in January 2015. Huni and the team's new roster had a successful Spring Split, finishing 2nd in the regular season with a 13-5 record, partly thanks to Huni's impressive performances on Lissandra and Rumble among other champions. This secured them a bye to the semifinals of the Spring Playoffs. Fnatic beat H2k-Gaming in their semifinal matchup, and went on to secure 1st place after taking a 3-2 win over Unicorns Of Love in the playoff final. This meant that Huni and the team would pick up 90 Championship Points towards qualification for the 2015 Season World Championship.
This also meant that Fnatic would represent Europe at the 2015 Mid-Season Invitational. Huni and the team had a relatively successful tournament, which they opened with a decisive win over Team SoloMid. The team also had a notably close group stage game with SK Telecom T1, but went on to lose the game. Fnatic finished the group stage in 4th place, meaning they would advance to the bracket stage. They faced SK Telecom T1 in the semifinals, this time playing out a close series, but ultimately losing 3-2.
Now with Rekkles on the roster instead of Steeelback, Huni and the team went into the Summer Season with confidence running high after their performance on the international stage. Fnatic finished the regular season with a perfect, unbeaten 18-0 record - and became the first team to achieve this in League Championship Series history. This meant a 1st place regular season finish for the team and a bye to the semifinals of the Summer Playoffs. Fnatic went on to win the playoffs, beating Origen 3-2 in a tight final. This qualified the team for the 2015 World Championship, where they would compete as Europe's #1 seed.
Huni and Reignover left Fnatic in November to join Immortals in December 2015 together. With a lineup including the two ex-Fnatic players, Pobelter, WildTurtle, and Adrian, Immortals were expected to be one of the top teams in the LCS based on their roster, and for the first six weeks of the split they lived up to - and even surpassed - those expectations. Huni and Reignover together extended their regular-season LCS winstreak from 18 games in Europe to 32 games overall as the team didn't drop a single game prior to week 7. However, in week 7 that streak was snapped as the team lost one game to reigning champions Counter Logic Gaming in week 7. They won the rest of their regular season games, but as the season progressed further they looked weaker and weaker as a team, and even seemed to falter against the last-place Team Dignitas, needing to come back against them to pull out a win.
With a top seed clinched into the playoffs, Immortals were guaranteed to face the lowest-seed team that won in the quarterfinals. That team ended up being Team Solomid, who were on a strong upswing after a sixth-place regular season finish. Despite their seeding advantage, Immortals lost 3-0 to TSM, with both their play and also their drafts called into question. Huni's champion pool limitations were highlighted as he picked Lucian top in game 1, followed by Graves and Gangplank, ignoring the meta-favored tanks of Ekko and Maokai on patch 6.6. They came back the next week to beat Team Liquid and finish in third place overall, with Huni playing the much more conventional Gragas and Poppy.