Religious question anyone..which is it now ,one or the other and why the contradiction?

Scholars believe that there are two different Gods. The God in the old testament apparently is evil and the one in the new testament is good. I wonder if Satan is the God in the old testament because when Adam and Eve ate that forbidden fruit they were shunned and Satan took over the world (which God had given to Adam) and then Jesus came along which is in the new testament.