***Disclaimer***
I am making no claim that this is the best way to kite the Shadows. I am not saying this is the only method. I am not saying that other methods are bad or in any way worse than this method. I am making no statements, express or implied about anyone or any other method. I am not guaranteeing that I will never change my method of kiting. This is simply the best method that I personally have executed on my caster. I am not posting this in an attempt to boast or otherwise impress anyone. This post is for informational purposes only.
Ok, so having successfully kited the Shadows more than once, I'll tell you how I do it.
Let's describe the layout. The Dais lies in the center of the North Wall. There are 8 doors in the room, two on each wall. The ShadowMaster sits on the Dais and with any luck will not leave it. The Shadows spawn at random doors around the room with the exception of the first 2, that always spawn at the North wall doors, D1 and D2.
-----D2--DDD--D1-----
|............DDD............|
|..............*..............|
D3...........................D8
|..............................|
|..............................|
D4...........................D7
|..............................|
-----...................-----
......|..................|
......|........z.........|
......---D5---D6----
Legend
DDD
DDD - This is the Dais
D# is a door, numbered for reference.
* is the initial Acid Fog Point.
z is the initial zone-in for this party.
0. Caster should have Quicken, Extend, Empower and Maximize. They are important in that order. Caster should be buffed with Cold Resist, Protection From Elements, FireShield-heat, Jump, Haste, (Feather Fall,) Blur, Displace, GH and Stoneskin. Caster should have equipment with Stride +30%, +X Jump and Feather Fall. A maxed Green Steel Cold Resist item would also be good, but I don't have one. The caster needs to have FireWall and should also have Acid Fog. (I have seen Incendiary Cloud work as well in place of Acid Fog.)
1. Cast Acid Fog directly in front of the stairs, (point marked by asterisk) or even partially on the stairs, but allow the fog to fall primarily on the floor. I prefer to run ahead of the party to avoid the lag as they run up the stairs. For this and all subsequent castings, the caster should have the mouse "target circle" ahead by a good amount. The spell should not land directly at his feet and it should not be at his maximum range. About 50-60% of maximum range is my guess.
2. Cast a Firewall in front of D1 from in front of the stairs, standing off to the East side. (North Wall, East Door)
3. Cast a Firewall in front of D2 from in front of the stairs, standing off to the West side. (North Wall, West Door)
At this point you should see one of the first 2 Shadows spawn directly in front of you. The effect looks like a Phantasmal Killer spell. If placed properly the Shadow will either spawn in the FireWall or directly behind it and will move through it almost immediately. What you can't see is that the other Shadow on the East Door (D1) spawns at the same time and will hit the FireWall cast there at the same time.
4. Run Counter-Clockwise.
5. Run diagonally toward D4. While running and jumping, cast a Firewall in front of D4 while in the air. (West Wall, South Door)
6. Run toward D6. While running and jumping, cast a Firewall in front of D6 while in the air. (South Wall, East Door)
7. Run toward D8, but do not cast.
8. Once near D8, turn sharply toward the Acid Fog and the bottom of the stairs. While running and jumping, cast a Firewall on the stairs. Do not try to make the wall cross the stairs in a perpindicular (East-West) fashion. A North-South wall placed on the stairs is sufficent.
9. Run toward D3. While running and jumping, cast a Firewall in front of D3 while in the air. (West Wall, North Door)
10. Run toward D5. While running and jumping, cast a Firewall in front of D5 while in the air. (South Wall, West Door)
11. Run toward D7. While running and jumping, cast a Firewall in front of D7 while in the air. (East Wall, South Door)
12. Etc. etc. etc.
That's it in a nutshell. After the intial fog and D1 and D2 FireWalls are set, the idea is to run around the room and cast FireWalls in front of every other door and refresh the FireWalls on the stairs at every opportunity. Always cast when you can. Even if the stairs or a door seems covered, cast again. As long as you are ahead of the Shadows, cast at every opportunity, which again usually amounts to every other door.
The "problem" with Backup casters is that the natural tendency is to become overzealous. They watch the Primary caster casting FireWalls all over the room and they want to join in the fun. So naturally the begin casting FireWalls on the steps. Next thing you know there are 4 FireWalls on the steps. It would take the Primary caster 4 laps around the room to get that many FireWalls on the steps. What is then most likely is that the Shadows will agro the Backup caster and wipe the party. This is the easiest way to fail with a backup caster. Scenario 2 involves the Backup caster "missing" the stairs and placing a FireWall on the floor. This is the second most common way to fail with a backup caster. I have also seen backup casters run around the room casting FireWalls at will changing Shadow agro. I can't say that I've seen this a lot, but it has happened.
Do not run through the hallway surrounding the main hall. This is a TRAP! The Shadows spawn randomly near the doors. If you are kiting Shadows down this hallway and one spawns in front of you, it's game over.
I don't usually make it around the room 5 times before our groups have killed the Shadow Master. One time, I didn't even make a third lap, before he was dead. Only once has my 2:30 Acid Fog dissipated before he was killed.
General Pointers
1. Don't stop, keep running. Even if you miss blocking a door, get it on the next run. As long as there is something blocking the stairs, there is no problem.
2. Jump! If you don't jump while casting you will die.
3. Skip a door rather than slow down or run into a corner. Keep moving.
4. Try to hit the stairs on every lap. Its not always possible if you have to refresh D8 or D1.
5. Cast if you can. Don't skip a door if you can cast and keep moving.
6. Try and stay "outside" of the pillars. Run between the wall and the pillars when possible, except the Northernmost set of pillars.
7. TURN! If you see a Shadow spawn in front of you, turn toward the middle. It's that simple. You are hasted and can just avoid him by turning.