Many, many weapons, mostly encrusted with old blood.
He is a big man. He is constantly dressed in old, broken armor, generally with dried blood all over. Any visible flesh is heavily scarred. He is unkempt, and many swear that his eyes glow with an unnatural light. Though many would not recognize his appearance, they always recognize the standard emblazoned prominently on his armor: a sword enveloped by blood-red flames.
He started life as Khass Brightwing, adventurer extrodanaire. He went through life with a half-humorous, half-arrogant outlook. There was nothing he could not do, no quest he could not complete with the proper allies and the proper weapons. He met Eamon Sianeth on one of his adventures, and saved his life. The two became fast friends, and started adventuring together. Eamon had a bit of a hero-worship complex, which frankly only stoked Khass’s ego. But, finally, after several years of adventuring together and reknown, the two went their separate ways, but kept in touch. And they started trying to out-do each other.
That was the folly that brought Khass down. He wanted to lead a raid to depose the ruthless Warlord Belos, and he got damn far. But close is never good enough, and Khass and his allies were captured.
Most of them died within weeks.
But Khass hung on, grimly surviving anything Belos could put him through. For over a year, he was a prisoner. Then, suddenly, Belos fell and the dungeons were thrown open and his old friend was there, halfway carrying him out.
When Khass finally came to himself, he realized he had had a revelation. It was sheer arrogance to think that one could not fall; this was a world for the strong. He had survived more than a year of extreme torture. He was one of the strong. Belos had fallen, he was weak. Khass saw the rules and morals of man for what they were, to his mind: mere masks, to keep the reality of the world at bay. Men had become weak.
Suddenly, he experienced a blinding rage at the weakness of man. He killed those tending to him; for what did the strong need the weak? He attacked anything that got in his way and started a fire that was to consume the house he was in. Eamon was his friend, but he had to be tested as everyone must. He survived the attack; Eamon was one of the strong, which gladdened Khass.
When he was thinking clearly again, he realized that he must bring his insight to the world; he must be the flame that tested men. Why else had he, who had once been an arrogant deluded fool, had this revelation?
And so, he began his crusade to weed out the strong from the weak. His old name no longer meant anything, and so he took a new one. He was the flame which tested the mettle of men, the Forge in which they would be made stronger.
Forge is violent, vicious, often cruel and homicidal, but he doesn’t think himself evil. In his shattered mind, he sees himself as the last hope of man, the one who can save them from devastating weakness.
He will often attack whole villages, killing and maiming indescriminately. If there are survivors, well, they’re obviously strong. Only the weak die.
If anyone thinks they can take him in combat, they’re welcome to try, but so far, they’ve all been weak fools.
He respects any that he considers strong, and if he feels they have been “tested” enough, he’ll leave them alone. Unless they mess with him.
He feels that there are some that have an excuse to be weak, such as children, and to a lesser extent, the very old (if they’ve survived this long, they’re probably strong. If they aren’t, the problem is self-correcting.) He will not intentionally harm these people, but indirect results of his actions are something else entirely. He feels that if they do suffer indirectly, that just makes them stronger.
Forge can be reasoned with. The trick is surviving long enough and getting enough of his respect in order to do it.