The fourth weapons of these characters are much easier to achieve. First, you must have 400 pts on the smith levels. Then, go to any area and go straight to the main camp. Leave anyone else you have at your main camp, though. Stay there and continually fight until you recieve 1000 kills. The 1000 kills achievement gives you two things to use. The first, if you have the 400 pts, is the fourth weapon. You only get the fourth weapon for that character, though. The second thing that happens is that you can have a total of 6 items instead of 5. If you are at MAX level, you get six. Even if you aren't at your MAX level, you will still have six at your MAX level. Those two things are the reason to beat 1000 people.
Any time you have to fight somebody at anytime. There are a couple of ways to make annihilated enemies your favorite passtime.
In order to start this, you must first find an opponent that has ALOT of people to fight. Then, you have to find someone on your side of the teams that has barely any troops. You must also have an ally from another area. Make sure to use the 'help from ally' order before you start this. Also, have a couple major tactics that remove alot of the enemy. The fire tactics are good like that. Also, put a backup general in each of those slots on the right side so that they come in later. When you get reports that your allies are coming, be ready. Right as they arrive, use your two other tactics. Their numbers are severely deminished, while yours jump so high off the charts. It's really fun to kill the enemy so easily.
This is simply logical, however, I believe it may be necessary to inform some people of a simple fact about this game.
During Empire mode, on the map you will notice that there are lines connecting the varying provinces. As I'm sure you know, these lines inform you of which province can attack another. If there is no direct line between the two, then it is not possible to attack this area from the area you wish to attack it from.
This is where the command "station" comes in. You station you best generals (or whoever you want to power up) in a province which has a clear line of attack. However, if you have only one clear line of attack, then you cannot select any reinforcements to aid you during the level and so you can only have a maximum of 3 officers and 3 lieutennants.
If, however, you have two provinces which you can attack the area from, then you can select up to 4 officers and 4 lieutennants, from any of the areas to attack. This allows the battle to go easier.
The same principle applies when defending an area, if you have only one area, then you can only have a minimum number of generals defending it. However, if you have two areas of your empires touching each other, then you can draw reinforcements from these areas to help defend it easier.
This means that, even if you do not have the maximum number of generals in each area (6), then you can still have a full army if you have stationed them correctly. For example, two officers and two lieutennants in one area, touching an area with two other officers and 2 other lieutennants, if attacked could draw 4 generals and 4 lieutennants and so still have a maximum army force.
By this rationality, we can see that if an area is surrounded by your forces, then the outskirts of your empire need not have any generals in them, unless they are liable to attack from other provinces or you wish to draw specific generals to defend a specific area. However, later on, on harder level settings, the enemy may be able to cause uprisings in your areas and so make officers under your control seek independance. But I do not know if this is the case as of yet.
It's quite simple really. If you want to gain more points/powerups etc on each level, as soon as the level begins, order the rest of the troops to simply defend their nearest base rather than attacking (try to make sure that the main camp is defended, by either defending the main camp itself, or defending bases which are in the immediate path to the main camp). This will ensure that only attacking enemy generals will be attacked by anybody other than yourself, (and none of these will be killed since they will retreat, if weakened too much, to a nearby base) and will also ensure that no bases get taken out, leaving all the pointage for your beautiful self.
(for those who don't know) You issue orders to each unit by going into the start menu (during a battle), selecting unit info, and selecting an allied unit, then a list of possible orders will come up, and you select "aid base" then select the base which you wish that unit to aid, and the unit should go and aid that base.
P.S. Sometimes it doesn't work right away, but after a minute or so, if the unit has not moved, simply repeat the order, and it usually works.