Nicolas Kriess

Nicolas Kriess was the late husband of Nightingale, and father to Nick Kriess.

13 Days
Not much is known about Nicolas before his marriage with Nightingale within the first universe. But when Nightingale fell deathly ill with their child, Nicolas chased up an old legend about a dagger that could possibly save her. He sacrifices himself, stabbing himself with the dagger in question in front of Nightingale. He dies and Nightingale mysteriously gained godlike power from his sacrifice.

Nightingale decided to spend nearly eternity to mourn over him when she went back in time, and named their son after Nicolas. This action made Nick disown his mother, and believe that she was the person who killed him.