The Outsiders

The Outsiders are a black-ops team of super-heroes not concerned with public optics. They are typically organized by Batman to go where the Justice League can not go. They operate as an alternative superhero team that doesn't require public or political approval for their actions, allowing more freedom.

History
The latest incarnation of the team was originally created to investigate the Dark Multiverse and the various powerful metal artifacts through Earth's history, such as: Aquaman's trident, Doctor Fate's Helmet, Dionesium, and other items created with Nth Metal. The team was made up of Black Lightning, Katana, Geo-Force, Halo, and Metamorpho and also investigated the connections between Metahumans and lands like Nanda Parbat, Themyscara, and Atlantis before going their separate ways. Any record of their existence and Batman's discoveries from their missions where sealed away in a secret Batcave under the Batcave, until Duke and Hal Jordan uncovered the truth; setting in motion Barbatos' invasion of the Multiverse.

In the aftermath of Dark Nights: Metal and Justice League: No Justice, Batman approached Black Lightning about leading a new team to deal with the fallout of the Omega Titans' attack and the destruction of the Source Wall. The team was officially re-activated after a series of terror attacks by the villain Karma. Black Lightning recruited Katana, Orphan, and Signal to form the latest iteration of The Outsiders.

Batman would later add Lady Shiva, mother of Cassandra Cain and one of the greatest assassins on earth, and Sofia Ramos, a newly realized metahuman, to the team.

After a lengthy conflict with Ra's al Ghul, the team went their separate ways and unofficially disbanded the Outsiders.

Black Lightning and Katana reunited with Metamorpho when the Yamashiro clan come to taken vengeance on Tatsu. The trio decide to rebuild the Outsiders and bring Duke Thomas into the fold. This time they decide to leave the fifth and final position vacant for anyone that needs their help dealing with a problem they can't solve alone.

Canon

 * The original Outsiders were created by Mike W. Barr and Jim Aparo, appearing in The Brave and the Bold #200 (1983). The team was formed by Batman as a counterpoint to the Justice League and consisted of superheroes who do not fit the norms of the "mainstream" superhero community. This incarnation featured Black Lightning, Katana, Geo-Force, Halo, and Metamorpho.