Malcolm is a character mentioned in Fallout 4.
Malcolm was a man who lived in 2077. Right after the Great War occurred, he and his brother hid in the Reeb Marina. Going against their original plan, they stayed there for much longer than expected. Over the next month and a half, a large tension built itself between the two brothers over their next location. It is hinted in-game that Malcolm finally killed his brother.
Malcolm is mentioned only in Fallout 4.