Quite recently I tried making a character similar to yours, surprisingly it worked quite well and I managed to get a kill list of 300 creatures, including 20 or so megabeasts.
The best contributor to my success was an artifact that I had found quite unexpectedly among a cheese-necromancer's hoard - An artifact grade steel greataxe - which was able to decapitate most everything I came across in a single blow.
Every manner of creature fell to my blade, and soon enough my adventurer was known throughout the land as a legendary fighter and completer of quests.
It fell apart however after I killed a werewolf and drank its' blood, granting me the power to turn into the beast at will.
It worked fine for quite some time, I'd fight until my adventurer got hurt then embrace the bloodlust to heal to full.
Unfortunately, I eventually ran into a bug, I could no longer carry anything with a weight without having my speed reduced to the minimum value, which I think is .0099.
It only happened after I transformed while I was already a werewolf, so I assume that was the cause.
I managed to *T*ravel back to my hometown, but not without being ambushed 6 times.
The first few combats were only won thanks to my luck and absolute immense skill at dodging, blocking, and similar skills that had been honed through several years of constant combat.
Eventually, I happened upon a decent strategy - by pressing the "." or "," key I could pass only a few moments at a time - allowing me to stand still and let the attackers come to me ensuring their swift death.
Upon reaching my home I talked to my old friends and asked to stay before retiring the character.
I checked each and every one of my stats, none of them were suspicious in any fashion.
And I tried multiple times to see if the bug could be fixed by turning back into a werewolf or even transforming while already one but unfortunately I had no luck.
Too bad too as I really enjoyed playing as Wyr Ancientanger the deceitful fortress, whose axe, Wornsilver the soft silkiness, slew untold horrors.