PHI Fusion

On September 20, 2017, Overwatch developer Activision Blizzard officially announced that Philadelphia Flyers owner Comcast Spectacor had acquired the rights to the Philadelphia-based Overwatch League franchise. With the purchase, the franchise became the first professional esports team to be based in the city of Philadelphia. Dave Scott, CEO at Comcast Spectacor, said that his decision to buy into the league was based on research that showed there were over 300,000 Overwatch players in the market. "I was surprised as we started to look at this seriously a few months ago, just the number of gamers worldwide being in the hundreds of millions," he said. "It’s amazing when you really get into it — 350,000-plus Overwatch players in this market."

On November 1, the franchise name was revealed as the Philadelphia Fusion. Shortly afterwards on November 3, their roster was revealed.

Philadelphia opened their inaugural season with a 3–2 victory over the Houston Outlaws on January 11. On January 25, Philadelphia upset the undefeated New York Excelsior, which marked New York's only loss in Stage 1. During the Stage 2 playoffs, the team defeated the Stage 1 champions London Spitfire in the semifinals, though they lost to the New York Excelsior, 3–2, in the stage finals. The team then missed both the Stage 3 and 4 playoffs. They claimed the sixth seed in the season playoffs They defeated the Boston Uprising in the quarterfinals, 2 games to 1. They then faced the three-time stage champions Excelsior, who the Fusion defeated 2 games to 0, which sent them to the Grand Finals. They faced the Spitfire in the Grand Finals; the Spitfire defeated the Fusion 2 games to 0.

For their 2019 season, the team was led by co-head coaches Go "NamedHwi" Se-hwi and Elliot "Hayes" Hayes. The Fusion had a solid Stage 1 performance, finishing the stage with a 5–2 record and making it to the Stage 1 Playoffs, but they lost 0–4 in the semifinals to the San Francisco Shock. After posting 3–4 and 4–3 records for Stage 2 and Stage 3, respectively, Philadelphia failed to qualify any other stage playoffs. A 3–1 victory over the Seoul Dynasty in their final regular season match gave the Fusion a 15–13 season record and qualified them for the Play-In Tournament. Philadelphia fell 2–4 to the Shanghai Dragons in the first round of the tournament, ending their hope of qualifying for the season playoffs.

Prior to their 2020 season, both co-head coaches Se-hwi "NamedHwi" Go and Elliot "Hayes" Hayes announced their departures from the team. The team found their replacement on October 25, 2019, with the hiring of former Seoul Dynasty head coach Kim "KDG" Dong-gun. Over the course of the 2020 season, the Philadelphia Fusion reached the finals of two of the three mid season tournaments: the Summer Showdown and the Countdown Cup, losing both to the Paris Eternal and San Francisco Shock, respectively. The Fusion finished the regular season in second place in the overall standings, with a 24–2 record. Advancing to the season playoffs, Philadelphia swept both the Los Angeles Gladiators and Los Angeles Valiant by scores of 3–0 in the first two rounds of the North America bracket. In the upper finals match, which took place on September 12, Philadelphia were handed their first loss of the postseason, falling to San Francisco by a score of 1–3. After sweeping the Washington Justice, 3–0, the Fusion advanced to the Grand Finals bracket. The Fusion's first match in the Grand Finals bracket was on October 8, where they were swept, 0–3, by the Shanghai Dragons. The following day, they were swept, 0–3, by the Seoul Dynasty, ending their postseason run. Fusion support player Kim "Alarm" Kyeong-bo won the league's Rookie of the Year award.

In the offseason preceding the 2021 season, the Fusion signed former Paris Eternal general manager Kim "NineK" Bum-hoon as their new head coach, replacing Kim "KDG" Dong-gun, who was released earlier in the offseason. Philadelphia relocated to Seoul, South Korea to compete in the league's East region; while they planned to bring their team, which was composed of many European and Middle Eastern players, to South Korea, COVID-19 variant outbreaks in these regions caused visa issues, preventing them from joining the team. As a result, the Fusion signed several new South Korean players to the team right before the start of the season. With a starting roster of veteran players, the Fusion began the season with a perfect 4–0 start in the May Melee qualifiers. However, they lost to the Shanghai Dragons in the following regional knockout, failing to advance to the interregional tournament. Plagued with ongoing visa issues, the Fusion qualified for the season playoffs, after defeating the Hangzhou Spark and Seoul Dynasty in the Eastern region play-in tournament. However, losses to the Los Angeles Gladiators and San Francisco Shock in their first two matches of the double-elimination tournament eliminated them from the playoffs.

The Fusion announced in January 2022 that they would continue to compete in South Korea as a part of the East region for the 2022 season. The team parted ways with head coach NineK and promoted Cho "J1N" Hyo-jin, who was the head coach of their Overwatch Contenders academy team T1, to head coach. Philadelphia released their entire roster in the offseason, aside from damage player Lee "Carpe" Jae-hyeok and support player Kim "Alarm" Kyeong-bo, and signed two rookies from T1. After the death of Alarm in November 2021, the Fusion signed two more veterans to fill out a five-man roster.

On December 30, 2022, Comcast Spectacor announced that from the 2023 season onward, the Fusion would be rebranding to the Seoul Infernal and relocating to Seoul, South Korea, where they would share facilities with T1, who is co-owned by Comcast Spectacor. The decision to move cities and change branding was met with criticism by fans who had supported the team.