Mass Effect: After Armageddon
A former N7, the first human Spectre is best known for saving the Milky Way from certain destruction during the Reaper War. Though there are many stories about how Shepard stopped the Reapers, each more outrageous than the last, little is known about the commander's war-ending actions on the Reaper-controlled Citadel. Shepard has not been seen since and is presumed dead.
Those of Shepard's allies who have survived the war remain influential in galactic affairs.