The Spring War was an event that took place ten years before the main storyline of the Witch Spring games and is the cause for the witch hunts. Masterminded by Jude and the Pope, they hoped to gain the powers of the deities by taking over their Springs, which they believed to be the source of their powers.
In the areas under the Pope's influence, particularly Vavelia and Derkarr, war broke out against the deities. Though the deities managed to hang on for a while, the Temple Lords in Vavelia were finally slain when their strongest guardian animal, the Maegrik Dragon Temar, was sent to Derkarr to stop an attack by the Ancient Dragons on Shubeth Village.
As Eirudy finds out, this incident was orchestrated by Jude in order to weaken the Vavelian deities. He stole the Nest of the Ancient Dragons, brought it to Regal, and bound it to Regal's life. The Ancient Dragons went to Shubeth to retrieve the Nest, only to realize that they couldn't harm Regal because of Jude's spell and were instead bound to follow all of Regal's orders in order to keep their Nest safe. However, because Jude and Regal anticipated the Ancient Dragons would come to Shubeth, Regal requested the aid of the Vavelian deities to drive them off. With Temar sent to protect Shubeth, Jude and the human armies were able to slay the Vavelian deities and bring victory to the humans' side.
With victory brought on the humans' side, this instigated the witch hunts over the next ten years that forced the remaining deities into hiding. Palace Warriors were trained to take on deities and either capture or kill them for a reward, which brought in many glory-seekers. Humans were taught to despise and fear the deities, and some of those who lost loved ones in the war came to blame the deities for it. Most of the deities caught were publicly executed or killed on the spot.
On the deities' side, many of them who had once lived peacefully in human villages came to despise humans and view them as traitors. However, some of those who lived away from human contact learned to fear the warriors, but were otherwise more interested in being able to coexist with them.
Furthermore, some humans did not agree with the witch hunts; notably, the royal family of Vavelia did not support the witch hunts, but the Pope had amassed too much power and influence for them to stop him. Some villagers who found themselves no less impoverished than before, or even more so, also believed that the deities' blessings were necessary and the witch hunts were a mistake.
Because of the efforts of Luna and Pieberry, Jude and the Pope are defeated, and Vavelia's Temple Lords are revived. As it turns out, the Vavelian deities were aware that this would happen all along, and allowed it to happen.