Eddie Winter

Eddie Winter is a character and side antagonist in the 2015 game Fallout 4 who serves as the main antagonist of the quest "Long Time Coming". He was a powerful pre-War mob boss in Boston who willingly became a ghoul through a radiation experiment in order to have eternal life and survive the War.

Winter is Nick Valentine's personal foe, having been responsible for the death of Valentine's fiancé, and this is proved when 200 years later, a synthetic Valentine hunts him down alongside the Sole Survivor.

Background
Winter was a cunning, influential and ruthless Boston mob boss who was involved in every kind of criminal activity, ranging from simple robbery to full-scale murder. The Boston Police Department issued a task force led by Captain Jonathan Windmark to investigate and possibly arrest Winter, launching Operation: Winter's End.

During the investigation, Winter ordered the assassinations of several people, including the fiancé of the lead detective Nick Valentine, Jenny Lands. This made Valentine even more dedicated to bringing Winter to justice, but the mobster made a deal with BADTFL and incriminated most of Boston's mob bosses, while keeping himself innocent and immune.

When tensions rose between nuclear warheads, Winter built himself a bunker underneath Andrew Train Station and willingly participated of a massive radiation experiment, turning himself into a ghoul and securing eternal life. Locking himself on his bunker, Winter lived peacefully and comfortably for 200 years while the world above him was destroyed in nuclear warfare.

Fallout 4
Unknown to Winter, Nick Valentine's memories and personality were transferred by The Institute to a prototype synthetic humanoid. Synth Valentine could not put his past behind him, and sought to hunt down Winter in order to finally obtain closure. After the Sole Survivor reaches a high affinity level with Valentine, the detective tells them about Winter and expresses his desire to finally bring justice to his fiancé's killer.

After all ten holo-tapes with the password to Winter's bunker are obtained, Valentine and the Survivor personally confront Winter, who mocks them and says that he managed to survive and live well for more than 200 years, not caring much about their discovery. Regardless, Valentine unleashes his rage and, with the Survivor's help, shoots Winter dead.

Trivia

 * Winter carries an unique .44 snubnose revolver named Eddie's Peace, which does 50% extra damage to limbs.