Cadre of the Immortal

The Cadre are individuals who sided with the Anti-Monitor in his war with the Monitor and his Challengers.

History
On October 12th, 1993, the stars to the tv show "Challengers of the Unknown" disappeared during an event called the "Atomizing." The Monitor recruited them to be the first of his own Challengers. Mobius observed this and began recruiting people to help fight back.

Mobius first met with Eobard Thawne, a criminal better known as Professor Zoom. Professor Zoom, in the first several decades of the 21st century, had a vendetta against Barry Allen that he desired to act upon.

Throughout the years leading up to this battle, Thawne worked with Mobius to create metahumans that would aid in the Crisis.

Crisis on Infinite Earths
Mobius began his spree of destruction in October of 2014. As the antimatter wave spread across the Multiverse, the Monitor recruited his own group of individuals to combat the Anti-Monitor. Mobius managed to get Psycho-Pirate away from the Monitor and convert him to his side.

When Barry Allen attempted to destroy the Antimatter Cannon, Eobard Thawne confronted Allen in a fight that went through time and space. Eventually, they arrived in the year 1992, where Barry saved his childhood self from being murdered by Thawne. Enraged, Thawne murdered Barry's mother.

The Psycho-Pirate remaind stranded in the Antimatter Universe for a long time after, even as the rest of the Cadre battled the Challengers on the streets of Metropolis during the Crisis. Psycho-Pirate would later be beaten by Wally West near the end of the Crisis.

Post-Crisis
Several members, including Thawne, Psycho-Pirate and many of the Fables escaped. Most of the other Cadre members either died during the Crisis or lost their abilities shortly thereafter (in cases of Mobius directly granting them powers, anyway). The Fables reunited with the Psycho-Pirate during the Infinite Crisis, but were defeated.