There aren't all that many weapons in the world today. But here is a list of the different weapons I've seen and how they seem to help you.
Club You pick this up from Clubius in the town hall. It is basically a big stick which lets you swing at creatures and hopefully hit them.
Glowing Club This is a club that some people managed to pick up in various places. There are a few different types of this club glowing a bit differently. Basically, they seem to be as effective as a normal club in combat, except that these glowing clubs are magical and won't let you swing until you have a certain amount of balance. (Keeps you from swinging out. Especially useful if you have trouble with weather.)
Dagger This is the dagger that you get from Master Fistus when you decide you want to be a fighter. It doesn't seem to do any more damage than a club, but you do seem to hit things a little more often. In technical terms, it seems to add a little bit of atkus (5 ranks perhaps) and also increases your slaughter level slightly (because of the couple extra ranks).
Short Sword The short sword is available from Witkus. It would appear to add a significant amount of Atkus (perhaps 15 ranks) and some Darkus (maybe 5 ranks). Consequently, your slaughter level also goes up.
Axe Available for sale from Pirate Henrik on Ash Island. This weapon increases your Atkus some and definitely adds Darkus training as well. (more than the short sword). The drawback is that all those extra ranks increase your slaughter significantly and you use much more balance when you swing.
Shiny Dagger This weapon can be made from a piece of metal and about 5000 coins at the Blacksmith shop. It increases your ability to hit, but at the same time seems to decrease your ability to do any real damage. Excellent weapon if you are just trying to tag things that you have trouble hitting normally. Doesn't significantly raise your slaughter (if at all)
Great Sword Available from Witkus. This is a really big sword that increases your Atkus and your Darkus by a lot. However, it has a very wide range of damage and it takes even more balance to swing than an axe. Because of this many fighters consider it to be too difficult a weapon to wield and not worth the bonus it gives you. Garibaldi says, "I noticed that I rarely did more damage than an axe, but always paid the price in balance."
Gossamer Once you reach a certain skill level, the blacksmith might offer to make one of these for you. You need to "practice" with this weapon in order to get good at it. As you get better at using it, you learn to swing only as hard as you need to in order to kill creatures. For example you may only get 3 swings in a row when fighting a Rage, but when clearing rats, you could get 6 or 7 swings before you needed to rest.
Fell Blade Once you reach a certain skill level, the blacksmith may instead offer to make you a fell blade. Again you will need to "practice" with this weapon before you can start taking advantage of it. I don't know much about how this weapon helps you, so if someone could let me know I would appreciate it.
Main Gauche This is a left hand weapon that some people have managed to pick up. It adds to your defense, and might help with attacking and damage as well.
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