Firstly, train regularly with the candles, eventually (after being successful many times in a row) you will unlock a self introspection battle... do not underestimate this... whether you find it too hard or too easy there is something to be learned.
If you find it easy to win then you must be exploiting faults in his style, therefore they are also faults in YOUR style that can be exploited by a smart enemy. If you find it hard to win then watch what he is doing, learn from him... the computer is suing your styles to their maximum advantage so pay close attention to how he changes and what stances he uses... there is much to be learned from that.
Second tip... if you can acquire the two moves "Netherworld" and "Draw&strike" then try the following form... arrange them as "Netherworld, Netherworld, Draw&strike" And assign them to a button you don't frequently use.
When in times of need I suggest you try this move, it leaves you open to attack if you get it wrong, but it done correctly it is almost an instant kill... it starts off with a long range thrusting stab to the abdomen, them proceeds with two thrusting slices through the gut (try to avoid veering off target with the second attack or the third will miss), all of which are maximum strength, high lethality moves and will almost certainly leave your opponent with very little health left and bleeding out... this even works on the Monk.
If you miss you are generally standing with your back to the enemy, so immediately switch to a defensive style and get out of there fast. I suggest you use this move when you are being charged as they generally lower their defenses until range when running at you, and since this is a relatively long range attack it gets them off guard.
Oh, and this is just a personal recommendation... I also suggest you try out the form: "Crouched slash, crouched slash, crouched slash" as it works well with most enemies, especially the lower class ones, it ducks bellow their defenses and is very fast allowing you to hit them multiple times before they recover, and if nothing else buys you time when in a hectic fight to plan a decent strategy.
Best of luck to you