He seems to have a Pip-Boy on him, filled with pre-War info, which gives off the idea that he may have been a wanderer, searching for the secrets of the old war.
An intermediate, human male, character. Symm shows up in Act 2, after the Prisoner realizes a docking clamp is needed. If the Ciphers are still alive, then Symm will be up near the condensers (Trig will direct the Prisoner to him). If the Ciphers are dead, he'll be in the main part of the village, angry and looking for revenge.
Symm has not appeared nor is he mentioned in any published game. He was to appear only in Van Buren, the canceled Fallout 3 by Black Isle Studios. It is not certain if he will appear in any future Fallout game.