I reincarnated As a goblin, damn it!

"What's this?"
I was born in a very different world. A world where magic is very important. That's not what surprised me. What shocked me and I didn't accept it was, I was born a weak green creature, Goblin. I was born as a Goblin. A very weak creature.
What can I do by being a Goblin, dead?
It would be sad if it actually happened. I don't want to die. I want to marry many girls first. I will make a harem. I can't waste this. Game system and magic. It really is Isekai and I'm the main character.