Petroglyph, the strategy game developer founded by key members of defunct Command & Conquer creator Westwood Studios, is developing its first microtransaction-based online game, due in fall 2009.

Published by relatively new Orange County, Calif.-based online firm True Games Interactive, Petroglyph's upcoming action strategy RPG Mytheon will adopt the "free-to-play" model, which typically allows users to download a game and play for free, while selling extra virtual items for revenue.

A press statement described the premise of the game:

Mytheon is an online microtransaction game that uniquely combines the best elements of action, strategy and RPG game-play with a heavy emphasis on collectability and combat. This visually stunning title is set within a fantasy universe steeped in unique mythologies from across the globe. Players will first embark on a rousing journey through the extensive lore of ancient Greece; with ongoing expansions to follow that will delve into exotic mythologies from the far-flung corners of history. With real-time combat and extensive customization features, Mytheon will offer infinite replayability through group, PVP and solo play as well as an integrated social networking feature set.
 Petroglyph's previous games were traditional retail boxed strategy games that include Star Wars: Empire at War and Universe at War.

True Games is also slated to publish the free-to-play online action fantasy RPG Warrior Epic in fall 2009, from developer Possibility Space.