[Hp]path of Fear

It's probably a story about an alien who travels back to his parents' generation and becomes a member of the Ravagers. Later, he follows Voldemort and breaks with his friends, and then chooses to overcome fear to atone for everything he has done. Harry met a new friend, and this friend always seemed to be looking at him. What is the relationship between this person and the notorious Death Eater Carl Coward, and what is the story behind all this...