In summary: you, the main character, were the first prototype created in the
Origin project. Fettel was your brother, as you were both conceived by Alma .
Alma was Harlan Wade's daughter, and she was used as a maturation chamber for
the Origin prototypes. After it was discovered that Alma could still reach out
to Fettel, despite being unconscious, Origin's directors decided to kill Alma,
and seal her body in that giant sphere within the Vault. This much is told to
us in the game, but then things get complicated.

After the credits roll, Genevieve Aristide is heard making a phone call to the
Senator, stating that the first prototype was a success. You can interpret
this to be in reference to the main character. Knowing this, it is plausible
that the entire point of the game was an extreme test of the prototype's
abilities, and that Aristide, with the Senator's help, created the situation
purposefully by re-opening the Vault. This isn't a far-fetched conclusion, as
there was a message left on a phone within the game that stated Genevieve had
called the Senator to bring in military troops. Under the guise of a hostage
taking at the Armacham building, the Senator provided the prototype with ample
soldiers to test his skills on. That soldier is you, and assuming you beat the
game, you performed up to expectations.

stopped shortly after getting blown out of the window by psycho girl