What if my original character was reborn in his world as a necromancer

My character was born in a world that was like ours the only difference was that their world didn't have technology, the world that he was born In was our past but the wold had one thing that we didn't which was magic

My character was born as a slave, his perents was a slave to a very powerful family and my character sadly had died very young but instead of seeing the gates of hell or haven, he was given a second chance