10 Shocking Times The Justice League Turned On Each Other
3. Starcrossed
The only animated entry on this list is the most iconic example of League betrayal outside comics. The original Justice League series finale sees Hawkgirl/Shayera Hol reuniting with the Thanagarians after they help the League foil an alien invasion.
Their sudden appearance is only overshadowed by the revelation that Shayera was an advance scout sent from Thanagar to establish the foundation for Earth-Thanagar relations. This is quickly revealed to be a ruse as the Thanagarians intend to destroy the Earth as part of their plan to develop a wormhole system that would improve their odds in bypassing their enemies' defenses. This results in Hawkgirl betraying the League and orchestrating their capture and imprisonment.
Fortunately, the League foils their efforts and drive the extraterrestrial invaders away from the planet. However, Shayera's betrayal is not easily overlooked and it alienates her from the rest of the team, especially Green Lantern, who was romantically involved with the Thanagarian. Due to her betrayal, she resigns from the League and is also unable to rejoin her people.
The three-part episode was an excellent conclusion to the first series and set a new status quo that would play out in equally dramatic fashion in Justice League Unlimited.