The attempted extinction of dragons was an enormous massacre by the Shadow Lord that resulted in the near eradication of dragons. The Shadow Lord, wanting to rid Deltora of its native protectors, sent its Ak-Baba to hunt and kill the thousands of dragons that roamed Deltora during the reign of King Lucan.
After the Shadow Lord's defeat at the Battle for Deltora, it realised that all out conquest of Deltora was not the way to win. It decided on a more subtle approach, as well as various contingency plans should it fail. These included the grey tide and Four Sisters. However, it knew the dragons of Deltora would sense its creations and destroy them with a fury.
To compensate this, the Shadow Lord worked on weakening the Belt of Deltora's connection to the Deltoran monarchs. Once their power began to wane, the Shadow Lord sent its seven Ak-Baba to track down and kill the dragons. The Ak-Baba would surround a single dragon and eventually kill it. They rarely fought two dragons at once, and anymore would force the Ak-baba to flee back to the Shadowlands. Although the dragons were many, their solitary nature kept them from joining forces against the Ak-Baba.
Secrets of Deltora
Deltora's greatest explorer, Doran, heard of the dragon's dwindling numbers and travelled around Deltora to seek out survivors of each dragon species. He was only able to discover a handful of dragons spread out among the seven tribes. Each dragon told Doran of how their species were being hunted, but they each ignored Doran when he pleaded for them to unify to face the Ak-Baba, as it went against their nature. Doran's attempts to plead to the people of Deltora for support also failed, as humans had come to view dragons as pests who ate their livestock and stole women with long hair to line their nests.
Eventually Doran convinced the last seven dragons to go into hibernation until an heir of Adin awoke them when the time was right. He intended for that heir to be Prince Gareth, but his message to the prince never arrived due to Chief Advisor Drumm's intervention. Because of this, the dragons were not woken until the reign of King Lief, during which the last of the Diamond dragons was killed in her sleep, though her species continued through her unborn offspring.
The death of the dragons marks one of the most crucial moments in Deltora's history. It allowed the Shadow Lord to place the Four Sisters inside of Dragon's Nest, Shadowgate, The Isle of the Dead, and the palace of Del, as well as the grey tide in the abandoned city of Hira. The death of the dragons also allowed the Ak-Baba uncontested mastery of Deltora's skies, which gave the Shadow Lord even more spies within Deltora in the years leading up to and after its conquest.