The 5th Dimensional Imps are usually short, goofy little pests with immense powers, that they all use to pester one or more Heroes in the DCU, however, according to The "What if?" Story "Whatever Happened to The Man of Tomorrow?", They don't reveal their darker true forms to 3rd dimensional mortals unless it's to toy with them.
Fifth Dimensional Imps were considered beings of infinite power that were native to the Fifth Dimension. According to Bat-Mite, imagination was considered the fifth dimension. Due to their great power, it was believed that they held no concept of mortality. The abilities of an Imp varied as they were able to travel both through time and Hypertime. Such was their control in the overworld that superpowered beings of the third dimension were powerless against them. In fact, Imps claimed to hold the ability to penetrate third dimensional space at any level and control it. Their abilities extended to warping space and even stopping time over a set area.
The science of the Fifth Dimension was considered so sophisticated that it appeared as sorcery to the people of the third dimension. Fifth dimensional engines operated on pure imagination to the point that they seemingly generated thought pollution. Among their weapons included the Multitude that was actually a spear in their native dimension but appeared as a horde of monstrous angels within the third dimension.
It was revealed that the fifth dimension exists outside the DC Multiverse and that the fifth dimension is one of the most vital factors that keeps the Multiverse from dying. Mxy explicitly states that the fifth dimension acts as the "blood" of the Multiverse, and the energy that flows within the realms of the Multiverse is quite literally the doing of fifth dimension. The first dimension is a singular point in the Multiverse, the second dimension is a singular line in the Multiverse, the third dimension is materialised objects, the fourth dimension is time itself and the fifth dimension is imagination and exists everywhere at once.
Fifth dimension is guarded by the Source wall and it requires the Source Wall or the imagination will start running wild and the fifth dimension will slowly start decaying and rotting away because the imps cannot keep up with the fears, hopes and imaginations of everyone. The fifth dimension is running out of lifeblood due to the Source Wall being broken.
It was revealed that Mxyzptlk and Bat-Mite are the two most powerful imps in the entire fifth dimension. Mxy is not a villain but rather a guardian angel who watches over Superman as Bat-Mite does over Batman.
Fifth dimensional imps are all individually Multiversal reality warpers as they live above the Multiverse and view the Multiverse as a fourth dimensional layer of space-time. The only dimension that exists above the fifth dimension is the sixth dimension, which acts as a control room to the entire Multiverse and is housed by the most powerful beings.
Some of the most renown imps in the DC Universe include: