The reason Saine was willing to send troops to aid the Water Mirror Civilization this time was largely because, when the Mechanical Civilization had suffered Qisha Time-Space's invasion, the Water Mirror Civilization had promptly extended a helping hand.
Saine was clearly a True Spirit Magician of the Wizard Civilization who deeply valued old ties and affection. Whoever had helped him in times of danger, he always kept a clear account of it in his heart.
Moreover, given that the Mechanical Civilization already intended to increase its purchases of the Water Mirror Civilization's distinctive ice element rule resources, preserving the Water Mirror Civilization's current sovereignty and continued existence would bring nothing but benefits to both Saine and the entire Mechanical Civilization.
Not only that, as the Mechanical Civilization's staunchest ally, the Light God Race presumably would never wish to see the Water Mirror Civilization so easily annihilated by Duolie, Lord of Dimension of Qisha Time-Space.
Although Saine had recently immersed himself in his experiments combining magic and machinery, he had never relaxed his attention toward the wars in other dimensional planes. He even remained in frequent contact with top-level beings such as the Creation God.
Even if he was too deeply engrossed in his laboratory to promptly learn certain critical information or the core thoughts of other civilizations' upper echelons, Lina and the others around him would immediately organize and compile everything, then specifically communicate it to him, ensuring that he always grasped the full picture of the time-space war situation.
Judging from the current overall resource structure and balance of military power in the Light Universe Time-Space, for a homeland super power such as the Water Mirror Civilization to firmly preserve its own sovereignty and continued existence would likewise bring considerable benefits to core powers such as the Light God