Kestrel is an agent of the Lords of Chaos and arch-nemesis to Hawk and Dove. The chaos lords M'Shulla and Gorrum created him as a formless entity that attacks enemies on the mortal plane by possessing human hosts. Hank Hall's girlfriend Ren Takamori would become Kestrel when he possessed her. He has also been a member of the Injustice Society.
In other media
Appears in Superman/Batman: Public Enemies.