Lord Dregg is the main antagonist in the last 2 seasons of TMNT 1987 and one of the main antagonists of season 4, TMNT 2012. He is an evil alien overlord and is treated more serious than the Shredder and Krang. He commands a large army of aliens. Dregg met the Turtles when he and his gang broke into the Federal Reserve Bank to steal the world's gold. The Turtles, however, foiled Dregg's plan thanks to their new friend Carter.
Dregg later manipulated the people of Earth into thinking that he was their savior so that he could rule the planet. He transformed dirty water into clean water to gain their blind trust. However, it was a machine that cleansed the water, not Dregg. The people built a tower in his honor. The Turtles still didn't believe him and confronted him. They destroyed Dregg's tower and Dregg fled the scene.
In the 1987 Teenage Mutant Ninja Turtles series, Dregg has blue skin and glowing red eyes. His head towers past his forehead in a black brace. He wears a purple suit and cape with a red and orange striped outfit underneath. His eyes glow brighter when he is either delighted or rageful.
In the 2012 TMNT series, his appearance is that of a purple winged insectoid with four eyes, a mouth that is always frowning due to the design of his lips, a tail similar to a centipede's with pincers on the end, razor sharp fingers on detachable hands, and a very muscular build, able to easily overpower the Turtles, April, and Casey single-handedly during their first encounter and meeting. Due to his insect alien physiology, he also has a hive mind to allow him to command his Vreen drones, and if their connection to him is lost, they effectively stop fighting and flee without Dregg to give commands.
- Lord Dregg's name is a play on the word "dreg". This term refers to and is synonymous with sediment, dirt, soiled items,the least valuable parts of a thing, and very bad persons.
- Lord Dregg is the first Shredder replacement in the 1987 series.
- He was voiced by the late legendary voice actor, Tony Jay, in the 1987 TMNT series, who also voiced Megavolt. Tony Jay was not only a popular voice actor for children's programming but an accomplished Shakespearean actor of stage and screen. He's noted as a legend in his own right.
- He was voiced by Peter Stormare in the 2012 TMNT series.
- Dregg was created due to the fact that Power Rangers was changing their villain at the time.
- Along with other characters from the Red Sky series, Dregg never got merchandise based on him.
- Lord Dregg in the 2012 series appears to take aspects of Maligna, the insectoid Queen of the Malignoids who was an enemy of the Mutanimals in the Archie comics.