Charles has always stood out to me as a very good general, look no further then the battle of narva for this, but he always seems to get overlooked in the conversation of great generals. I'm talking from a strictly military point of view as he was obviously politically inept and had his fair share of problems(giving Russia the chance to recoup after the battle of narva), but speaking on a battle by battle basis could he be considered up there with a man who barely but did beat napoleon in open battle? I chose Wellington because in my opinion you napoleon was a better general than both Charles and Wellington.
Comparing rulers/generals is always kinda difficult. So I'd say this is the wrong subreddit for this question, but anyway. I believe Charles was way better than Wellington or Napoleon at leading armies. The thing many forget is, that the British and the French had massive, well armed, well trained soldiers. Sure Napoleon was a great commander, but he had the best army in the world at that time. That really helped him to fight ( of course this is partly because of his policies etc, but doesn't change how good of general he was). Charles did have a good army and well trained, but he fought against such crazy odds, yet he won at ease. His army was relatively small, fighting against multiple powers in Europe with a small army is quite a challenge (both British and French started having massive armies during, before and after Napoleonic wars). Only thing stopping him was the great frost and how cosacks weren't helping him as much as he expected.
Charles himself was great for the morale of his troops, great at commanding his troops and so on. I truly believe he is better of a general than Napoleon or Wellington.
I just realized I accidently called Duke of Wellington, just Wellington, ignore that :P