Marko

Marko is mentioned in a note titled "Dead end" found on a wastelander's corpse directly north of the MDPL-21 power station.

Background
According to the note, Marko killed the author's family in front of his eyes and let the author live, who then started tracking Marko, seeking revenge.

The author, however, did not pick up Marko's trail after one week of search. Feeling himself a failure, the author commited suicide.

Appearances
Marko is mentioned only in Fallout 3.