Swords and Magic

A boy was suddenly Reincarnated into a Baby after a Fight with a Powerful being.

Now after 500 years he is suddenly Reincarnated into a body of a newlyborn baby,

At 4 years of age he had dreamt of the powerful being that had killed him and was told that in less than 20 years he will come back into the world to wreak havoc again. With less than 20 years of time to get stronger, will our protagonist be able to finally defeat that can cause chaos and wreak destruction unto their world.