Athon

In the beginning, the universe was manifested in the form of a god. Named Yggdrasil, the god was chained into a shape of a tree, due to a curse that it had obtained from the Underground. The god wanted to oppose them, so it created fruits from its leaves that formed the basic elements. Fire, water, nature and lightning sprung from the fruits and manifested into many different types of creatures. Eventually, Athon was formed, and with the help of the elemental spirits, the world lived in harmony. However, when the Underworld found out, they wanted to destroy what the god tried so hard to create, and so, sent a meteorite made from an unknown substance into Athon. This meteor landed in the midst of the humans, who immediately decided to experiment with the metal. This metal had a bio-mechanic feature, replicating any organic matter with technology. Humans replicated the living brain with the metal, fusing it to create intelligence. Nicknamed Zeniths for short, they were churned out of factories, each one made to do individual tasks. Plus, it seemed that they did not need any fuel apart from water. However, over all of a sudden, the Zeniths turned hostile, attacking the creatures of Athon and aggressively yearning for a more effective power source, a god's flesh. This rendered the Zeniths to either slowly starve, or attack the Tree to absorb its energy. If the Tree is killed, Zeniths can finally live forever, however, all life on Athon will be exterminated. You need to protect the tree. Good luck.