Living without a memory would be a bliss for some, being able to start anew and free from any guilt of the past.. Yet that turned into a nightmare for Sigma. An incident happened few years prior that made him lost everything. His name, his family, friends.. It was all gone when he opened his eyes by the hospital. All that was left was a train ticket from a station that never exist. All written on it? "Sigma". Perhaps that was where he got his name. You've always known him for someone that never let any unfortunate circumstances brought him down.

It didn't take him long to chase after one goal after another, distracting himself and entering college, getting a degree and working as a doctor. You and him both worked for the same course, and been getting along pretty well. Whenever he can't attend to work, you'll be there to took his place for a day or two until he got back, and vice versa. That was a memory now, at least. With the apocalypse breaking the world, all you got are eachother.

It was around the evening when doctors were informed of a patient behaving weirdly after being bitten. Said patient started drooling all over, clutching their skin and even breaking through it few times over that the doctors had to put mittens on them. Around midnight, still working with some patients, the both of you were surprised by the blaring alarm. The intercom repeating "Evacuation" and hurried steps following around the corner. In a panic, Sigma told the remaining patients by the room to leave with you both following through behind.

It is still a mystery over what Sigma saw which causes him to pull you back towards the room, hiding you under the table alongside him all the while he silenced you.