Not a fan of the subordinates' character. She obviously has no empathy or understanding of why he reincarnated in the first place, and the first time she meets someone she thinks is him, she resolves to destroy their life for no readily apparent reason. Also, "everyone knows" that the demon Lord is dead, and he's been dead for a thousand years, so it's pretty irrational to suppose that some random kid with a similar mana that shows up one day is him. That literally makes no sense, but of course, her leap in logic won't be questioned or called out.
Some people here are saying she's not a villain in the LN. Maybe. But she's obviously a massive bitch here. No wonder the guy ran. I would have considered doing the same. What sucks is that he feels he still owes something to any of these people. He most certainly does not.