There is no specific word for it in my mother tongue. Imagine the situation when he meets a group of people, maybe he just met them, with few words he can start a fight among them and the turn against each other. Any word for that?
Heh, in 1960's British English, one of my favorite movies called a character like that "a real mixer". I've never heard that in everyday speech in America, though.
I can think of words like "quarrelsome" that could be used that way, but usually mean getting himself into fights instead of others.
Well, if no one else comes up with something, maybe you can bring "mixer" back into fashion. I'd love it if you did.
In (fairly vulgar) BrE slang, there's...
shit-stirrer - someone who makes trouble for other people, especially by making known facts that they would prefer to keep secret.
In some conversational contexts you could use He's a [right/real/etc.] stirrer to tone down the vulgarity (which doesn't have to imply a deleted shit, but many native speakers would assume it did).
For more formal contexts you might consider...
troublemaker - a person who habitually causes difficulty or problems, especially by inciting others to defy those in authority.
It's worth paying particular attention to the different "common contexts" following especially in those two definitions. But they don't always apply (i.e. - you might call someone a troublemaker because he habitually reveals sensitive personal secrets which will lead to conflict among others, just as you might call him a shit-stirrer if he's always encouraging others to defy authority).
Having said that, I must admit that because those two "standard" associations are so well established, I might sometimes "lapse" into the vulgar usage even in conversational contexts where I would otherwise tend to avoid it, simply because it's the only really precise term for that specific sense.