First born as the name suggest means that the first being born in the Universe. He is also known as the first child of Universe, and no one can rival him in the strength and knowledge.
As the first being born, the universe provided him with the fate and luck of all the being of the Universe which made him the one and only being that has ever reached the height of Eternal God level cultivation in this universe.
But as the living in this universe started expanding the original power of First born started decreasing and reach near to only half-step Eternal God.
First born realized that his end is about to come so he decided to destroy all the problematic beings from the Universe.
Since First born was the first being of the Universe he treated everyone equally and when he saw that human race are being bullied for being weakest among all so, he gave them shelter.
