Pain and Terror are major antagonists in Borderlands 3, being high ranking members of The Children of The Vault, and are the hosts of, and run, the Bandit carnival of chaos, Carnivora. They are based on, and voiced by, real life magic and comedy duo Penn and Teller.
At some point in the past on the violent planet of Pandora, Pain and Terror banded together to increase their odds of survival on the ultra hostile world. They would eventually join the Children of The Vault and pledge themselves to Tyreen and Troy Calypso. Rising through the ranks and have an exceptional talent in entertainment, Pain and Terror would go on to be the famous hosts of the bandit festival of death and destruction, Carnivora, where they would live stream all kinds of games and challenges often being brutally gruesome and almost always ending in the death and dismemberment of the participants.
As the Calypso Twins' crusade to unearth The Great Vault continued, they kidnapped Patricia Tannis, and sent her to Carnivora, where her murder would be the main event of the festival. As The Vault Hunters fought their way through the carnival, events proceeded as planned, with the bloodshed the heroes caused actually earning them the respect of Pain and even from some bandits, as the ratings were going through the roof as the bandits witnessed their kin being killed. Upon reaching the end, Pain gave the heroes the option to choose their own intro music for the final battle. Arising with the robotic horror The Agonizer 9000, the final showdown to free Tannis ensued, and The Agonizer 9000 destroyed. Falling out of the broken heap of metal, Pain and Terror were incapacitated then killed.