|Love interest(s)||Unknown Woman|
|Relatives||Rachel Amber (speculated)|
|Appearance(s)||Before the Storm|
A Mysterious Man can be seen on one of the promo images for Life is Strange: Before the Storm who seems to be a key figure for the plot of the game. It was the revealed that the game's story is about Chloe and Rachel unconvering a "dark family secret", which is why it's speculated that this man might be Rachel's father.
It's possible that it's the same man Chloe and Rachel observe meeting with an unknown woman in one of the scenes that were shown in the pre-release footage that was releaved at the E3 2017.