If batman was going toe to toe with no weapons or prep a CHAOS space marine would win. Give Batman intel, one hour prep & required loot and Batman would definitely win.
Batman is insane and has been since he was a child. His refusal to kill is part of his psychosis--that's why he will never break:it's because he's already broken. HOWEVER Batman is capable of killing almost anyone in DC Comics, he just chooses not to. He's an expert in almost every field that others spend their entire lives to perfect in just one--almost all fields of math, science, deduction, stealth, physical combat, engineering & so many others he's on par with all of their life-dedicated experts/geniuses. He's the ultimate badass & jack of all trades.