The role of the DEO is to monitor those with extranormal superpowers and to prevent any threat to the general public. However, in Action Comics #775 there are a couple of rogue agents being defeated by Superman. Manchester Black, the leader of the Elite, suggests they are responsible for the creation of fellow team member Menagerie, saying that "These guys run a triple black alien immigration service that takes the galaxies' cast-offs an' turns them into weapons for the highest bidder. The West Nile glop in New York is one of theirs from the Microbio Division." The DEO was responsible for the "orphanage" seen in Young Justice, in which Secret was kept, although a later conversation between Director Bones and Agent Chase suggested the conditions in which she was kept were not official policy. Another such orphanage was seen in the 1999 Titans series. The DEO has protected important aspects of Washington D. C. from telepathic intrusion. A rogue department of the DEO manages to convince Green Lantern to scan various heroes presumably to detect a body-hoppingsuper villain. Instead, the data is used to create a new version of Amazo. Chase, Mr. Bones, Green Lantern and other heroes shut down the division. Amazo is destroyed and Green Lantern deletes the relevant information. Batwoman becomes a reluctant agent of the DEO after the agency learns her identity. Mister Bones, director of the DEO, believes himself to be the illegitimate son of Col. Jacob Kane, Batwoman's father. DEO agents discover that Beth Kane, Batwoman's identical twin sister, is alive and capture her. Bones blackmails Batwoman into helping the DEO uncover the secret identity of Batman in exchange for Beth. Batwoman and her allies are unable to rescue Beth, and Bones attempts to kill her. Agent Asaf, suborned by Batwoman, shoots Bones in the head and frees Beth. Asaf then claims that Bones was mentally unbalanced.
In the comics continuation of Smallville, the DEO appears as a Washington DC based agency under Director Bones dealing with threats like Felix Faust and Dr. Phosphorus. Under Trevor, the DEO took steps in employing individuals like Cameron Chase, and even heroes to their causes, like Oliver Queen/Green Arrow and Diana Prince.
In other media
Film
In the 2011 film Green Lantern, the DEO appears as an agency under the secret support of Sen. Robert Hammond. His son Dr. Hector Hammond is given the assignment of doing the autopsy of Abin Sur by one of the main heads, Dr. Amanda Waller.
In the 2015 CBS/CW television series Supergirl, the Department of Extra-Normal Operations employs Kara Zor-El's adoptive sister Alex Danvers as a scientist and operative. This iteration of the agency is led by former CIA agent Hank Henshaw. Thanks to J'onn, the DEO now is less prejudiced against non-humans and focused on battling rogue extraterrestrials in addition to occasional criminal, metahuman and terrorist threats. It is learned in season two that Superman was a member of the team. Through Supergirl's alignment with superheroes from a parallel Earth, the DEO is aligned with S.T.A.R. Labs and accessing their technology for dealing with their own metahuman and parallel universal threats. In Season 4, Alex has been named as the new director of the DEO from J'onn.
At the end of the four-part Arrowverse crossover, "Invasion!", Kara speaks with the succeeding President of the U.S. of the Earth-1 universe Susan Brayden; she informs the new chief executive that the United States government on her universe founded the DEO for monitoring and countering extraterrestrial threats, and the president agrees that her administration would establish their own agency in response to the Dominators' attacks.
During the final part of the later Arrowverse crossover, "Crisis on Infinite Earths", following the multiverse being rebooted, Supergirl's universe was merged with others including Earth-1's to create Earth-Prime and the DEO was altered to become a subsidiary of LuthorCorp.
Video games
The DEO had a brief appearance in the intro level to , where they acted as adversaries to both Batman and Catwoman, the former due to mistaken association with the latter, and the latter due to stealing classified data.
