Dragon Ogres/Ogors™ are a bunch of Chaos-worshipping, half-man, half-dragon centaur monsters in Warhammer Fantasy and Age of Sigmar. They are huge, terrifying monsters that eat lightning and crap thunder... and are also exceptionally lazy. No really, they are giant creatures that sleep 24/7 that only wake up when there's a big thunderstorm going on. They're probably the laziest Chaos-worshippers next to Nurgle's lot, except they would actually get shit done and wreak havoc on the world if they cared to do anything about it. Like the dragons they were fighting since time immemorial, they existed long before the Old Ones arrived at WarhammerWorld™.
For those of you who know your classical mythology, they are a reference to the giants of Greek myth, mothered by Gaia and fathered by Tartarus to make war upon Zeus and the Olympians for imprisoning the Titans who had fathered them. These giants were noted as having ugly, human-like upper bodies and monstrous, reptilian lower bodies like their siblings Typhon and Echidna.
Dragon ogres are immune to all forms of electricity and even draw sustenance from it. They often bathe in lightning before heading into battle so that they may store the energy and unleash it like a "Lore of Heaven" spell. Like centaurs, they have a normal humanoid upper body and a four-legged monster body below it. This gives them a speed advantage against other large creatures like giants while allowing them to wield gigantic, two-handed great weapons in battle. Their scaly skin is impervious to ranged attacks like arrows and bullets. They are also really, REALLY FUCKING BIG, so big that primitive humans mistook them for mountain gods and worshipped them.
As a dragon ogre ages they grow larger, until they can be called a Shaggoth. Thanks to a primordial pact made with the forces of The Warp, all dragon ogres are immortal and infertile. Having made this bargain to save themselves from a long, slow extinction at the hands of the dragons and Old Ones, they now live as thralls in eternal bondage to Chaos. They have no need for food nor is there anything that truly challenges them so they sleep until the call for battle comes. Apparently, they all hope for some sort of apocalypse to end their insufferably boring torment, so they're probably happy now.
Dragon ogres are NOT related to OGRES despite the name. Ogres actually bitch-slapped the dragon ogres in their first encounter and chased them out of the Mountains of Morn, showing how even the most ancient of Chaos' mortal followers are absolute failures.
Known Dragon Ogres
Krakanrok the Black: The eldest of all dragon ogres and the one who forged the pact with the Chaos gods for all his race. Archaon met him while on his quest for the Slayer of Kings (the daemon sword holding the Greater Daemon U'zuhl). The Krakanrok was holding the weapon to his chest as he slept, so Archaon called his strongest companion over to pry away one of his claws. Unfortunately, the sword's
cardaemon alarm went off and Archaon, in fear for his life, killed his companion to sate the sword's thirst for blood and make his escape before Krakanrok could wake up. During the End Times, a loud thunderstorm foreshadowed his awakening, but he never actually showed up in any of the material. Like many characters of Warhammer Fantasy, he reappeared in the Age of Sigmar as a Dragon Ogor™ Shaggoth™ the size of a mountain. Apparently his infertility was cured, because he's going around spreading his progeny and being called The Progenitor.
Kholek Suneater: Krakanrok's more famous and playable first-born son. He was also there when the pact with Chaos was made and did something so horrible to seal the deal that the sun was covered by a thunderstorm and would never again shine on Kholek's form. From that day, he was followed and heralded by terrible thunderstorms. During Asavar Kul's invasion of Kislev he single-handedly broke Kislev's walls with his TOTALLY NOT A THUNDER HAMMER Starcrusher, destroyed the Gryphon Legion as it tried to flank the Chaos armies, and smashed many temples in the city. During the End Times, he rampaged uncontrollably until Settra cut off Kholek's head with his own khopesh in a no-holds barred, Super Saiyan-tier battle. In Total War: Warhammer he is a legendary lord for the Warriors of Chaos faction, infamous for being straight-up the fucking best Chaos lord in the game thanks to his high defense stats, ability to run around the map, and give you free armies of Dragon Ogre Shaggoths.
Skaranorak: One of the first-born of the Dragon Ogres and possible Kholek's brother. This beast is said to have terrorized the Brigundians (ancestral tribe of Averland) many times until Sigmar went to his lair in the Black Mountains and woke him up with a hammer to the head. Sigmar skinned his hide and made it into an impenetrable cape to honor his strength, and the Brigundians joined Sigmar's empire as a result. At some point in time, a Sigmarite friar had a violent vision that blew out his zealot mind when he stumbled upon the place Skaranorak and Sigmar had fought. Seven temples/museums were built in recognition of that event and one of them houses an eight-foot tall rock believed to be a claw of Skaranorak.
Dragon Ogre Chaos Champions
Way back when they were introduced in Realms of Chaos it was possible for dragon ogres to claim the title of Chaos Champion and lead both their own warbands on the Path to Glory and their own armies in Warhammer Fantasy. This was never referenced in later canon.
Dragon ogre champions are always warriors, never sorcerers, and had the second-lowest chance of starting with Chaos Attributes of any of the playable Champions in that edition: a "starting level" dragon ogre had a 25% chance of having d2 Attributes, and even a 25th level dragon ogre will only have D6+1 Attributes. By comparison, a 25th level Beastman champion will have D6+3, and a 25th level Centaur champion will have D6+2. Only Minotaur champions had less. A dragon ogre champion always starts with a number of lesser dragon ogres as his initial followers; when he wins further followers, he can roll on either Beastmen or Minotaur follower tables to generate them as he prefers.
Age of Sigmar
Even after the Old world blow up, the Chaos Gods never considered Reincarnation as a valid way to escape debts.
They Once Lived in Azyr because of all the lighting before being kicked out by Sigmar, and renaming themselves ThunderScron TM in that memory.