After launching in English late last year, Riftbound, Riot Games’ League of Legends trading card game (TCG), has quickly grown into one of the most popular TCGs to date. The game had a big presence at this year’s Gen Con, featuring not one but two large booths that fans could stop by to learn to play, meet some of their favorite creators, and buy convention-exclusive merch. During the show, GameSpot had the opportunity to sit down with Riftbound game director…