Before they began their attacks, the Green Revival had been working on creating Project Spider, the first in what they planned to be many genetically modified humans capable of taking the energy absorbed by their "Creeper" bio-weapons and converting it into seeds which could be planted to revive numerous plant species which had been rendered extinct.
Although he does not directly appear, Spider is referenced in Kindle. Aduro can find numerous clues which reference the Green Revival's work on Spider.
After Kindle, Green Revival and their labs were shut down. As Project Spider was nearing completion, they had attempted to find a way to "brainwash" him into total obedience. When the power was turned off, this process ended partway through, destroying all of Project Spider's memories.