How to defeat Baron von Ratsworth

This guide is for low-skill hardcore adventurers. Others should just buy a big grenade and throw it.

According to the KoL wiki, Baron von Ratsworth is a scaling monster and he gets more powerful when you do. And he also gets more powerful with the number of ascensions.

Wiki says:
atk = moxie + (3 + #ascensions, max 12)
def = muscle + (3 + #ascensions, max 12)

This means...

After 1 ascension:
His hit chances = ~50%
Your hit chances = ~50%

After 4 or more ascensions:
His hit chances = 100%
Your hit chances = 0% (you'll be hitting him on criticals only)

Hence you cannot rely on ordinary attacks after the first one or two ascensions.

General tips

NO muscle/moxie increasing equipment

Every stat increase applies to your opponent as well. You may think that it does not matter if both your and your opponent stat is higher, but that is not true. Higher muscle means higher hit points, but the power of your weapon or spell stays the same. That means you'll need to hit more times.

Instead of the Doplhin King's crown or Viking helmet, wear a simple pail you get from the artist, asshat, or summon a coconut shell.

Basic meat pants, mariachi pants or even nothing is better than the sticky meat pants or knob goblin uberpants against the baron.

Regarding weapons, pick one with highest power, elemental damage (like the asparagus knife) or bonus spell damage if you rely on spells (silver butcherknife, knob goblin tongs or even little paper umbrella). Avoid any muscle or moxie boosting weapons, especially the epic weapons or moxie and muscle classes.

Regarding other gear, a dirty hobo glove is a good thing, a basic or improved foon is a handy off-hand item for spell casters if you are willing to invest the clover.

If in trouble, fight beaten-up

Beaten-up effects lowers your stats and hence your opponent stats. This lowers your opponent's HP and you have a better chance to bring him down with one hit.

Fight him soon

You want to fight the baron as soon as possible (level 4 is good). When you are strong enough to kill the rats, you are strong enough to kill the baron. Waiting longer only makes the battle harder, because he grows stronger and your gear (grenades, spells, non-enchanted arms and armor) does not.

Pastamancer/Sauceror way

Mysticality classes have easy time killing the baron. If you are low enough level (or at least beaten-up), just throw your spell and he should be dead in one turn.

Get silver butcherknife or knob goblin tongs, buy Ravioli shurikens/Stream of salsa if Spaghetti spear/Salsaball are not enough. Or get the foon.

If you are too high level, you would have to get better spells and equipment. So - kill him soon. You want the ring and the swill asap anyway.

Since you should have no problems, winning in 1 round, a volleyball familiar is probable best choice.

Disco bandit/Accordion thief way

If you have access to a powerful-enough permed spell, using the Pastamancer/Sauceror way might be easiest for you as no extra gear is necessary.

Having high moxie means that baron's attack will be high and his defense will be low. Hitting him with ranged weapon should be possible, but he will hit you as well and much harder. Therefore you may wish to equip a melee weapon and use Moxious maneuver while maximizing the difference between moxie and muscle.

If that tactic does not work, try using items doing damage like the cheap cigar butt, possessed tomato, Colon Annihilation Hot Sauce, or hand grenegg. These you can easily pickpocket before the quest. Having minimal stats (low level, beaten up) is crucial for these items to be effective.

Later, you can use items from the cola battlefield and healing potions. Though this is a suboptimal strategy since you'll be wasting meat.

A deleveling/blocking familiar like barrrnacle or levitating potato is a plus.

Seal clubber/Turtle tamer way

Muscle classes without skills would have a hard time defeating the baron. Your attacks will mostly miss, while baron's will mostly hit.

With Eye of the Stout and Lunging Thrust-Smack, you should be able to hit the baron and kill him with one hit. Because (it is believed that) the Eye of the Stout bonus is relative to your muscle and baron's bonus is absolute, you should keep your muscle high. This means that one of the rules state above does not apply: you should be higher level and not beaten up if you are trying this approach.

Without skills, you must rely on items. Since you cannot pickpocket the early combat items, you must wait for the cola battlefield or get the knob goblin elite uniform and buy them from the goblins.

An alternative strategy that can be effective early is to get the chronic indigestion skill. This is not easy as it requires adventuring in tower ruins, bat hole and getting spices and jabanero pepper from the hermit.

An attack/healing familiar like cocoabo can help. Healing items may be necessary.