Fable III

I found the easiest weapon to fully upgrade is the slimquick.

All you need to do is
1- get fat (eat lots of pies and fish from the stalls in bowerstone)
2- spend 8000gold (I bought 4 houses in bowerstone, but spend as you want)
3-kill 150 ugly creatures (Hobbs and hollowmen are your best plan as around mourningwood there are plenty)

Once the last upgrade is done the achievement will pop up. Also if your lucky and can get it from your shop soon as you get to brightwall or a friend to gift you 1, it's an easy weapon to progress through the story with and help upwards the 500 melée kills

All weapons in the game, outside the starting Hero weapons and any downloadable or bonus weapons, are Legendary Weapons. Go to your Sanctuary and go to the weapon room to look at your weapons. If you press Y while looking at a weapon it will list 3 objectives for you to complete while using that weapon.

Find a weapon that best fits your alignment (Use weapons that require good actions if you play a good character) and look the easiest to complete. Everyone gets different weapons in their game, but you can check this link to see what all the weapons and their requirements are:

http://projectego.net/fable-3/legendary-weapons

Once you complete all 3 objects for one weapon, the achievement will unlock.

Upgrading the weapon "Ol' Malice" was really easy to do. This weapon can be bought in shops in Bowerstone Market, Aurora, or in Brightwall Village. If you don't have this weapon in your world you can trade for it online. Or, if you have the weapon 'Slimquick' then refer to ABG Karlos' solution for upgrading that weapon.

Here are the upgrade requirements for Ol' Malice:

1: Hooligan - Smash 50 crates
This is really easy to do by fast travelling to Bowerstone Industrial and breaking every crate you see. You should get this in one visit to Bowerstone Industrial even if you haven't smashed a single crate yet.


2: Featherbrained - Kick 100 Chickens
Simply walk up to a chicken and press A to kick it. Repeat this 100 times and you're set! Good locations to find chickens are in Driftwood straight ahead from the entrance by the farm and in Brightwall Village over by the chicken races in the corner. There should be 2-4 chickens in each location.

x RepoUK x said that you can also find chickens in Silverpines (center), Aurora (center) and Millfields (behind Timmins Towers).

3: Explosive - Kill 100 enemies with an unweaved Fireball spell
Simply equip your Fireball spell and make sure it's not combined with any other spell. Then get to work killing 100 enemies. You can easily kill the Hobbes and Hollow Men scattered throughout Mourningwood.

After each upgrade, take out your rifle and try to fire it and it should flash brightly. Do this 3 times and the achievement is yours!

A really easy cheat I found for killing 200 short enemies on Mallett's Mallet, (not sure if other weapons require it) is, provided you have the DLC Traitor's Keep, is to go to the Godwin Estate and keep playing the hobbe dance party mini-game, with Stuffy the fish, until you kill enough hobbes.

Like ABG Karlos already said, I found Slimquick the easiest one to reach the requirements too.

The weapon:
Slimquick appears in one of the three weapon stores (Brightwall, Bowerstone Market or Aurora). If in your game it don't appear you need to trade with another player, or enter another player's world and search at the three stores there.

The requirements you need:
- Get fat (just eat pies from far southeast pie stall at Bowerstone Market);
- Spend 8000 gold (self-explanatory :))
- Kill 150 ugly creatures (I choose hobbes and I'll explain why)
Some places have shaman hobbes, that invoke more hobbes to the battle. You can grind kills from these shaman, just kill the summoned hobbes (generally 2-3, depending the shaman) wait for the new sumonning, rinse and repeat, and off course don't kill the shaman until you get all your kills ;) I grinded around half of my hobbe kills during the pest control quest at Driftwood from a shaman at a shore on the second group of hobbes you encounter. This shaman in particular summons the weakest-one-hit-kill hobbes that I saw in the game :). For the 150 kills you will need 20-25 minutes using this method.

The popping:
Each of the three abilities, when unlocked, make your weapon shine for a few seconds and is shown on the screen what your weapon just gained. When the 3rd shinning occurs your achievement will pop. The shinning ONLY occurs when you take your weapon and attack (even the air :)).

Hammer of wilmageddon:

Step 1- equip shock magic and shock kill 100 bad critters, ( I fast travel to mourning wood where you see troll magicians spawning groups of 3, kill the three every time they are spawned and try not to kill the wizard).

Step 2 rinse and repeat with fire magic.

Step 3 take that hammer and smash 100 hollow men.

Step 4, you got the achievement the headache free and faster way and upgraded your fire and shock magic even further.

I would suggest Wolfsbane Sword (you get it in the mission where you gather dead wolfs parts to bring out the ghost - it's before you complete the rebellion party mission):
- kill enemies at night (easy)
- kill wolves (the chillbreath caves and around the area, use charged attacks for 1HKill)
- kill ppl with charged sword attacks (see above+hollowmen - 1hk).
Sorry for not stating the exact numbers, but they are pretty low (50-80 each). Got this before finishing the Rebellion's last mission while doing misc quests.