Its all very metaphorical. “From his mouth comes a sharp sword” doesn’t sound like the usual weapons practices of the GrecoRoman era! 

Even if we take it as possible from the all powerful God via magical powers, we have actual contradictions about things like the name of the rider on the white horse. “he has a name inscribed that no one knows but himself ” seems to contradict “his name is called The Word of God” and possibly contradicts “On his robe and on his thigh he has a name inscribed, “King of kings and Lord of lords.””

So this is imagery used to relay the important message, probably here being the power of the Word of God.