Main characters who are spiritual siblings to Orka (from Bloodsworn Saga) and John Wick (from the movies)

I'm looking for books with characters who are on a mission, are dangerous, are NOT sassy, NO lengthy monologue, NO diaglogues for the sake of seeming cool. They don't have to be retired assassin's or retired warriors. In fact, I'd prefer characters who's an apprentice or an amateur, and yet has a composure like Orka and John Wick

I like adult fantasy with no romance (sub)plots. And something less than 400 pages