The Chaos Beasts are legendary creatures of Lore that are summoned and raised by the 13 Lords of Chaos in different ways. There are 13 different Chaos Beasts in all, and all were raised in their respective locations.
- The first Chaos Beast is the three-headed Lake Hydra, a creature that arose from the lake and unleashed destruction upon Chiral Valley until a heroic warrior sealed it away using rune magic with the Runix Cube, afterwards hiding three pieces of it all over the valley. It was freed by Escherion through the use of the reassembled Runix Cube.
- The second Chaos Beast is the Rock Roc, a creature thought to have been extinct. It was hatched by Vath through the use of the Chaos Gemeralds forged for him by the Dwarfhold dwarves.
- The third Chaos Beast is the O-dokuro, a giant Yokai skeleton that had been sealed in the Rift of Time for many years. It was released from the rift by Kitsune, who used the stolen Hanzamune Dragon Koi Blade to open the rift. After its initial defeat, a second battle against its disembodied head follows.
- The fourth Chaos Beast is the Dracowerepyre, which was originally an ordinary red dragon until it was captured by several Werepyres and dragged to Wolfwing's lair, then bitten by Wolfwing himself under the light of the Mystic Wolf Moon when his powers were at his strongest.
- The fifth Chaos Beast is Pony Gary Yellow, a triceratops/dragon hybrid that belonged to Kimberly Freeman as a plastic dinosaur toy. Kimberly sent the players back in time to the time of the dinosaurs to fight the enlarged, now-living Pony Gary Yellow.
- The sixth Chaos Beast is the Mana Golem, a being of living magic that was created long ago by the mages of Arcangrove as a last resort but sealed away in the para-elemental plane of magic due to being too dangerous to fully control or destroy. It was freed by Ledgermayne to assist in its desire to seal off all magic from Lore itself.
- The seventh Chaos Beast is the Chaos Sphinx, the greatest deity in the Sandsea, resting in the Sand Castle since ancient times. Zahart and his Djinn, Tibicenas, used the Heart of the Sphinx (which had literally been lost in the sands of time) uncovered by one of their slaves to animate the Sphinx.
- The eighth Chaos Beast is the Naga Baas, an undead Gorgon that was created by Krellenos from a random Serpentress through usage of an Un-Chaorrupted Arashtite Ore.
- The ninth Chaos Beast is Kathool Atchoo, a giant kraken-like monster who was awakened through the defeat of the three Proto-Chaos Beasts Carnax, Fluffy the Dracolich, and the Dragonoid. He first appeared in DragonFable and later appeared in MechQuest.
- The Chaos Manticore is the tenth Chaos Beast chaorrupted by Maximillian Lionfang.
- The Chaos Harpy is the eleventh Chaos Beast unleashed by Xiang after Evil Xing fused with Good Xang.
- The Chaos Dragon is the twelfth Chaos Beast brought alive from the dragon statue by Chaos Lord Alteon after he, in his madness, unwillingly murdered his own eldest heir, Princess Brittany.
- The Eternal Dragon of Time is the thirteenth Chaos Beast resurrected by The Hero.
- Every time a Chaos Beast is raised, one of the archways on Drakath's Chaos Portal is activated.
- The Chaos Beasts resemble and are inspired by different mythological creatures.
- An attempt at creating a Chaos Beast, namely the Chaos Beast Attempt, was done by Exos, who wanted to become a Chaos Lord. Interestingly, the Chaos Beast Attempt resembles the mythological Chimera, just like the real Chaos Beasts resemble other different creatures of mythology.
- It is said that a design notes post mentions a part of the Book of Lore where the Mother of Monsters was sealed away by dragons, and that her resurrection may be caused by the activation of all 13 archways through the summoning of all 13 Chaos Beasts. According to Queen Brittany of a future Lore accessed from the Time Library, a creature called the Conqueror would've arrived to Chaorrupt everything should the players have failed to stop the Conqueror from being freed. The Conqueror may be the Mother of Monsters herself. It is later confirmed in the Thunderforge chapter that the Mother of Monsters is the one who made Drakath into the avatar of Chaos, and waits for him to free her, and that once all 13 Chaos Beasts are locked, the Mother will then be freed into the world of Lore once more.
- The Chaos Dragon is actually The Twelfth Chaos Beast and not the Eleventh since Lady Celestia says that its the Twelfth and that a museum quest for it is not released implying that the releases are out of order chronologically.