The God King died suddenly at the beginning, what can I do?

Introduction: Qin Hao was an ordinary mathematics teacher who fell off the roof of a building to save his students. Traveling to a different world, I started out as the younger brother of the God King. I didn't do well in my previous life, but this time I was cast into a good child, and I started out as the God King's lap. Then from now on, won’t we have as many advanced skills, elixirs, and magic weapons as we want? What? The God King is surrounded by enemies? Bosses, please forgive me, I'm not familiar with him! Just met today! The God King fell, and I woke up in a strange continent. Fortunately, the God King’s supreme artifact was with me. See how I develop secretly and counterattack to become the king!