During the DICE Summit in Las Vegas, Bethesda Game Studios' Todd Howard shed some light on Fallout Shelter - the extremely successful vault management simulation that was launched last summer on Android and iOS.
Last time Howard checked the game had racked up more than 4 billion sessions making the most played Fallout game of all time, even beating the others combined (though we're not quite sure how you'd count sessions with the old games back in the day).
Clearly, Bethesda struck gold and it remains to be seen if they have other mobile plans for the future. Howard did mention that the project arose from a need within the team to work on something smaller and more contained as opposed to the massive openworld RPGs they are known for.
Thanks, DualShockers.