Deever Tweed and his cousin Dumfree resemble each other so strongly that you would take them for identical twins. They are in fact cousins, known as Tweedledum and Tweedledee, both as a play on words on their real names, and because they resemble Sir John Tenniel's depictions of those characters in Lewis Carroll's Through the Looking Glass.
The Tweeds always conduct their criminal activities in partnership with one another. Fat and lazy, they prefer to mastermind criminal schemes and let their henchmen carry out any necessary physical activity. The Tweeds will often use their extraordinary likeness to each other to dupe their opponents into thinking there is only one of them.
Tweedledee and Tweedledum first encountered Batman and Robin ( Dick Grayson) when the two cousins were conducting a series of robberies in Gotham City. Batman and Robin captured the Tweeds and have defeated them on subsequent occasions.
The duo tried a plan to take over Gotham's underworld by sparking a demonic war between multiple forces. They escaped the wrath of the survivors by getting themselves accidentally arrested.
Major Story Arcs
While investigating a murder scene, where a commuter train full of passengers have brutally killed each other, Batman fallows a train tunnel down into the subway system. There Batman is attacked by Tweedledee and Tweedledum. He is able to fight them off but notes that they are not acting like themselves. The cousins are full of rage. After the cousins run away and trap Batman under some rubble, he tracks them to a building top near by. There Batman learns that the cousins are working for Mad Hatter, who is trying make Gotham city mad like him. Batman stops Mad Hatter and the twins and saves Gotham once again.