As Joshua Williamson approaches the end of his four-year tenure on The Flashhe's pulling out all the stops. The upcoming story arc, "The Legion of Zoom," features some of Barry Allen's greatest enemies uniting to destroy him. However, this alliance could have happened much earlier in Williamson's run.

In an interview with CBR, Williamson says that he originally planned to introduce the Legion in issue 25 of The Flash. The idea came during a DC creative summit.

"We had this whiteboard and — it's really funny because Tom King is the in the picture — behind him you can see all the plans we had," he said. "The Bat-Cat Wedding was on there, all the stuff about Dark Nights: Metal was on there. And on there, you could see the words 'Legion of Zoom' next to '25' because I was trying to introduce the idea of them in that story. So even back then, I wanted to use that name and that idea but we didn't get around to it until now. And I'm glad we waited until now, I just wanted to tease it back then."

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The Legion of Zoom consists of the time-manipulating Turtle, Gorilla Grodd, the Trickster and Captain Cold. Judging from the name, it would seem that either Eobard Thawne — aka the Reverse-Flash — or Hunter Zolomon/Zoom is behind the group's formation. In any case, this group spells trouble for the Scarlet Speedster.

The "Legion of Zoom" story arc begins in The Flash #757, written by Williamson and illustrated by Howard Porter. The issue goes on sale June 10.

KEEP READING: The Flash Gets a New Supervillain Team: Here Comes the Legion of Zoom