Arrow: 10 Best Characters Who Only Appeared In One Episode
9. Roger Hayden/Psycho-Pirate
The first character from the crossovers on this list, adopting Psycho-Pirate to the live-action realm was a strong indicator of the CW's grand plans with its sprawling franchise. His appearance in Elseworlds (alongside the Monitor) heralded the incoming Crisis on Infinite Earths and its multiverse-spanning implications.
In the crossover, Hayden was an Arkham Asylum inmate who briefly escaped during a massive breakout caused by John Deegan after the latter needed a distraction to evade Oliver and Diggle.
Hayden was later apprehended by Batwoman and re-admitted into the asylum, where he befriended Deegan. The new multiverse saw him steal the Medusa mask from the Kahndaqi Embassy and use it during a brief criminal career.
The mask gave him the ability to control people's emotions and be acutely aware of them. In addition to this, he had an uncanny knowledge of future events and alternate timelines, including his involvement in a devastating battle between the Flash and the Reverse-Flash in 2024.