Next four characters speculation based off the silhouettes of the recent thumbnail : r/DNFDuel
Dungeon Fighter Online Elsword Shadowbane Video game, DNF, game, video Game png | PNGEgg
Female Nen Master - DFO World Wiki
Exorcist - DFO World Wiki
Saw some confusion as to which classes the teased DNF duel classes are, so here are my guesses. Who knows though, they could theoretically attempt to mislead us on purpose. Spoilered in