- "So then the Flash, we hatched a plan to gather all the remaining meta-humans into one place for a final showdown. They called it "World War M". It was glorious. Two forces on opposing sides of the stadium. The tension built. No. So the two forces charge into battle, and when they do..."
- —H.R explaining the conflict to Cisco[src]
World War M was an event that occurred on Earth Nineteen.
The Harrison Wells of Earth Nineteen described World War M as a "final showdown" between the meta-humans on his world. They were gathered in a stadium as part of a plan concocted by H.R. and The Flash, and two sides were pitted against each other. Tension built until the two sides charged into battle. Wells described the event as being similar to the movie Gladiator, which on his Earth was known by the less popular title Sweaty Men.
- "Monster" (mentioned)