MC is creating an imbalance of power in that other world with special goods that appear out of thin air, it will end terribly for them. But since the author looks like another slavery apologist, I guess that's not going to happen.
Considering the guy goes back and forth between worlds he basically is in no risk. The fact he hasn't even spent time in the world but was ready to accept slaves says a lot
chapter 1
skip everything
straight to... SLAVE.... am I right??
while in actuality, I feel like a real merchant at that similar period of time, seeing an oblivious seller like that, would tell his goon to tail him, capture him, and torture him to spew where he got the stuff
Lol, classic generic wish fulfilment. Average looking kid finds a way to another world, gets rich selling ordinary Earth junk and buys beautiful slave... all in the first chapter.
Well, at least there's no adventurer crap or cheat battle skills.