Cause Of Death: Committed suicide by shooting himself. Why It's Important: Only because it changed absolutely everything. Eobard Thawne, aka Reverse-Flash (the main villain of The Flash's first season) was an ancestor of Eddie, so his existence was entirely dependent on his being alive. By sacrificing himself, Eddie ensures that Reverse-Flash doesn't actually exist, and thus couldn't do any further damage in the future. Aside from dying a hero in the arms of the woman he loved, his death and the impact on the timeline also caused the singularity to open above Central City, which led to the death of Ronnie Raymond, Jay Garrick losing his speed, and the various breaches opening up across the city allowing Zoom and a number of his metahuman minions to cross through from Earth Two.