The Zero Civilization definitely possesses the ability to open the Star Gate. After all, being a Demigod Civilization, they must be capable of doing so, but it likely consumes a lot of energy.
If the Star Gate in the previous life was opened by the Zero Civilization with the purpose of having human superpower users help retrieve the Reincarnation Source Material for them, who was it that threw the Reincarnation Source Material into the Abyss Demon Nest?
Before the Star Realm Merchant obtained the Reincarnation Source Material, it was in the hands of the Shadow Demon King Erebos.
And the Star Realm Merchant definitely conducted fluorescent plant experiments on Blue Star in the past life, and learned that Blue Star is a world where they can thrive.
Therefore, the behavior logic of the Star Realm Merchant Civilization in the previous and current lives must be the same.
