Nexon and Softmax. The latter is porting the former's Dungeon Fighter Online beat-'em-up to the Xbox Live Arcade delivery platform, where the title will boast a freemium business model (meaning you download the client for free and pay for items and upgrades).
Nexon and Microsoft are splitting localization duties as the game will be released in eight languages worldwide. The console title -- Nexon's first -- will be exclusive to the 360. DFO features six character classes (with subclasses available at level 18) and further advancement possible at level 48 via an awakening quest.
[Thanks to Prime Synergy for the tip!]