2D MMO Dungeon Fighter Online could quite possibly be the ... That's certainly what developer Neople is hoping for, at least. It's not obvious at first, but Khazan has deep ties to the DNF series ...

an action-adventure RPG developed by Neople. Players can find an NPC in the game called Danjin, a merchant who sells hard and other rare trinkets to the player from the Dungeon & Fighter Universe.