It looks like The Flash is potentially adapting the DC Comics’ seminal Flashpoint for it’s third season but that wasn’t the only major comic book storyline that we may have been introduced to in the finale.
In order to beat Zoom in the race for his life, Barry created a time remnant of himself, which also attracted Time Wraiths which Zoom said in the episode had been after him. They got a hold of Zoom and seemingly transformed him into the Black Flash!
In the comics the Black Flash is a grim reaper of sorts for speedsters who takes the spirits of the departed back to the Speed Force. While technically a villain, Black Flash is more of a personification of Death than a traditional Big Bad.
Now did the show actually introduce the Black Flash? Based on the color change to his chest logo and ear bolts as well as the rotting face… it’s not certain, but sure as hell seems like it.
At one point, Barry Allen even became the Black Flash in The Flash: Rebirth, which was written by The Flash Executive Producer and DC COmics’ Chief Creative Officer Geoff Johns.