All of the storytelling, none of the player choice. The Mass Effect anime is still on the way from Funimation, and, as social media manager Justin Rojas revealed at SXSW ScreenBurn, it's focusing on Mass Effect 3's James Vega.
Mass Effect: Paragon Lost is being written and created by Funimation (who usually works primarily on existing content from Japan) working with EA and BioWare, and tells Vega's backstory before his appearance in Mass Effect 3, which includes some "epic" things, Rojas assured.
Funimation picked up some anime stars to work on the visuals, including studio Production I.G and a character designer from Eureka Seven (presumably Kenichi Yoshida). We'll see how this Texas studio's collaboration with Japanese artists on a Canadian sci-fi license works out this year -- "We're estimating fall or so," Rojas said.