Actually this achievement is for getting all characters to level 50.
QUICK EXP:
Here is my favorite way to quickly get exp...
Start with Guan Du(Cao Cao forces) and chose the character you want to raise. Now if hes at lvl 1-19 put the difficulty on easy any thing over 20 try to play on hard, never play on normal when trying to quickly lvl. your self up its harder then easy but gives you no extra exp. So playing on normal will only slow you down-You may also want to consider playing on Master difficulty around lvl.40 it will give you an extra 50% exp, but most officers seem to suck too much to easily pull it off. When your prepping your officer equip your fastest horse (preferable Red Hare King) and try to use a weapon with Flash(easly the best weapon ability in game). Once battle starts head directly for Bai Ma Fort (on the right side of screen) and kill first two officers(Shen Pei and Xun Chen). Next up will be Yuan Tan, kill him then Yuan Shang will arrive kill him as well(they will both drop 200 exp) Yan Liang(killing either Yan Laing or Wen Chou is Battle Target 1) and his officers Yan Rou, and Chen Zhen are next kill them as well(Now is a perfect time to use a tome if you have one). Now head to Yan Jin Fort and kill the two officers attacking it. Yuan Xi will show up next kill him(another 200exp). Next is Wen Chou with his sub-officers Lu Xiang and Lu Kuang(another good spot to use a tome) and finally Gao Lan.(he will also be worth 200 exp). Both forts will now be ok if neither fell during the attacks so your battle target 3 will be secured. Next head to Wu Chao Camp and lure all 8 officers into a circle around you. using you tomes kill them all(save Yuan Shao for last) and you'll get an ass load of exp. Your Battle Target 3 should aslo be complete(Guan Du gate east and west not breached).
NOTES:
1.Every officer you kill with a tome will drop 200exp.
2.When your officer levels up always go for tome related abilitys first. Tomes are the key to leveling up quick.
3.Getting 10,000 exp plus on Guan Du is very possible however it depends on lots of other little factors...
The difficulty, witch officer your using, what lvl they currently are, officer ability's, your horses speed, your current weapon and its abilitys ect
4.Hard plus 25% exp, Master plus 50% exp, Chaos plus 50% exp(should be one hundred damn it)
5.Every 100 kills is an extra 100 hundred exp.
6.Dont forget to pick up all exp even if its only worth 10
HOW TO FIND SPECIAL HORSE:
Getting a good horse like Red Hare King can be a pain because its all about luck and sadly I have found no easy way of getting them...here is what I do know.
1. There are a total of 5 horse kings that I know of and I believe it to be all of them.
2. Each horse is color specific*example to get Red Hare the horse must be red.
3. When you first receive a horse after a battle its bio under the picture of the horse must read "His eyes consider the world and he has a heavenly physique".
4. Here is each horse, their color, and special ability...
a.Red Hair King-Red-Able to run as fast as Red Hair
b.Grey King-White-Able to swim much faster
c.Ebon King-Black-Increases damage inflicted on enemies while running
d.Dapple King-Dark Brown-When landing from a high jump enemies are damaged by a shock wave
e.Auburn King-Light Brown-Able to charge throw large crowds
5.Once you obtain the horse you'll need to raise it with an officer that has the ability Horsemanship. There are a total of 8 officers from which you can use, but once you start raising a horse with a character do not use that horse with any other character(even if they have the horsemanship ability) or you will not get the King version.(learned that the hard way)
a.Doug Zhou
b.Lu Bu
c.Zhang Liao
d.Xiahou Dun
e.Guan Yu
f.Ma Chao
g.Sun Jian
h.Sun quan
Ok now on to finding the appropriate horse...
1.Select Battle of Chang Ban and pick Liu Bie's force.
2.I don't believe difficulty plays a factor in obtaining a good horse...though once again I can not confirm this. I would suggest trying on the easiest difficulty and if it does not work turn it up to normal or hard.
3.Next select two officer's(if you don't have a friend to help you just boot up a second controller and have him/her just stand some where safe) with the Lady Luck ability. Their are a total of 6 with it and here they are...
a.Yuan Shao
b.Liu Bie
c.Guan Ping
d.Xiao Qiao
e.Xu Zhu
f.Zhen Ji
4.When battle starts pull up the officer screen(Battleground) and locate 2nd Refugee group(Near a bridge in the very top left corner of map). Move to their position and save them by killing the officer chasing them in a giant circle(WTF?). Run around and you'll see a ramp that takes you up to a small camp, the box with the saddle is just before this. Now go around and quickly kill as many officers as you can to find another saddle(the holder is random). This was a very good level for me because the very first time I tried this I got Red Hare King...however I never got any other good horse this way so I may have just gotten lucky(though I only ever tried a couple of times).
NOTES:
1.If you have a horse with the Find Saddle ability take him with you, the more horse saddles you get in a single run the more likely to get a special one.
2.This strategy can be mirrored on any stage, you just need to know were the box that contains the saddle is.
3. Not 100% sure but I believe the best(if not only) way to get one of these special horses is to break open the saddle boxes located in each level.
4. If this just doesn't seem to be working for you consider putting it off for awhile and completing other objectives you may have in the game(reaching lvl 50 with all officers, clearing all officers musou campaigns, ect) you'll find them eventually, just dont forget to check your gathered saddles at the end of battles.
5.Good luck and happy hunting!