If the story is serious, then the primary opposition, the antagonist, must be serious as well.
Now, his (named and thus actual characters) henchmen both low and high tier can be comical in some fashion, either as part of a dark, sadistic side or that they are genuinely incompetent at their job which makes you wonder just why in Andramada did the Big Bad hired them on in the first place?
probably his wife's lame brother that she insisted he hire on because he can't hold a job because he's so damn stupid. So the Big Bad put him on the front line in the hopes of killing him off. But the brother was so damn incompetent that they couldn't even die when sent on suicide mission after suicide mission and thus his troops ended up adoring him and the Big Bad had to promote him or risk an uprising amongst his men. Killing the brother gains the Big Bad's approval, but the player can actually recruit the brother because why the **** not? Also the brother, when the big bad is killed, becomes the new Big Bad, but he's a total bro and gives up the moment he finds out that his opposition is the Brotagonist and they go on an excellent broventure!