I Work as an Alchemist in Douluo

Tianchen, a Blue Star man, accidentally traveled to Douluo Continent, but why is it different from the Douluo Continent I saw? What is an alchemist? The evil soul commander was born ten thousand years in advance? (I've seen too many Douluo movies that are the same, so I dared to break away from the original plot and write a book for the first time. I'm so sorry)