If they are scared of twins, why not simply have the 2 children at a different place? If they see only 1 at a time, they won't realize they are twins... problem solved.
So is the protagonist just a walmart brand Shirou? Also "I'm a swordsman". I guess if the definition of a swordsman is anyone who "uses" a sword then yeah I guess he counts. He is technically "using" swords, just not in the regular way. Though an archer is more fitting...
@ supermonkey123 probably some kind of revolution happened to give slaves more rights, so slave traders came up with a new term ("It's not slave abuse if they're just objects").
I like this mc. Finally a protagonist with some balls and he doesn't hesitate to kill if the situation calls for it. Also clearly his morals are all right.