"Crisis on Infinite Earths: Part Four" is the eighth and midseason premiere episode of the eighth season of Arrow, and the one-hundred-sixty-eighth and most recent episode overall. It aired on January 14, 2020.
The Arrow part of the Crisis on Infinite Earths crossover was co-written by Marv Wolfman, who co-wrote the original Crisis on Infinite Earths comic in addition to co-creating the characters who made their debut in the novel including Harbinger, The Monitor, Pariah and the Anti-Monitor.
While DC Extended Universe films is not impacted by The CW's Arrowverse, Ezra Miller's version of Barry Allen did make a brief appearance during the Crisis on Infinite Earths crossover event.
However this is the first time Ezra Miller's version of Barry Allen is called the Flash. Making it possible it might affect his universe in future films involving him.
This marks the first time that the DCEU Films and Arrowverse have crossed over.
In the comics, Maltus is a planet whose inhabitants, the Maltusians, are race of beings that include the Guardians of the Universe, the Controllers, Krona and the Zamarons. They are most affiliated with the Green Lantern Corps.
When the Paragons are spread out throughout the speed force, they are sent to past events in the Arrowverse including: