Sub-Director Null Party Dungeon Solution

Access to the gate is the same as for Canach Solo Dungeon Solution elsewhere in this forum.
Map is the same but there are many more mines.
There are Mine Detectors at the entrance. You only need one.
Sub Director Null is in the same chamber as Canach was to begin with, wearing a battle suit.

The entire party should bring as much DPS as they can manage. Ranged stuff is good, but not needed.
Bring party heals, party regeneration, AOE heals, AOE regeneration, etc. Stick together.

1. Disarm all the mines up to but not inside the chamber. Throw away all but one Mine Detector. Optionally, throw them all away. NOTE: Disarming mines outside the chamber was merely a precaution in the event of a party wipe. It is actually possible to get to the chamber without setting off any mines. NOTE: getting close enough to disarm any mines inside the chamber will cause you to be moved inside the chamber with Null.

2. Enter the chamber as a group, bring down his shield. If someone has a Mine Detector, use it to clear mines along the right side of the chamber going back to the far "corner" while the others crash his shield.

3. Entire party move as a group along the right hand wall to the far "corner." Fight from there in a close group to maximize healing benefit. Null will follow you. DPS him. Person with Mine Detector keep mines within range friendly - do not stray from group to extend range to additional mines. Feel free to drop the Mine Detector and do DPS during any (brief) periods when all nearby mines are friendly.

4. There will be a message about him increasing his shields; it will suggest using mines. Other than the Mine Detector option already discussed, ignore this. DPS him.

5. There will be a message warning you that he is releasing random ambient energy orbs (I forget the technical name) and suggesting some course of action. Your party is in the corner precisely because the orbs, which hurt very much badly, do not go into the corners. Ignore the message.

6. If he moves away from the corner, you have three courses of action. One: stay and wait till he comes back (he will). Two: follow him (risky because of the above mentioned orbs). IFF you follow him, STICK TOGETHER - essential for healing the party - a party that scatters, dies.

6a. Option Three (recommended): Use pulls - jerk him back into your corner. One of the successful parties I was with had to modify its tactics when they discovered that pulling Noll away from the Guardian diminished his ability to heal. This precipitated the death of the puller because she was too far from the healing. This inspired an ill-advised rescue attempt which precipitated the death of said rescuer. This precipitated the death of the rest of the party because of decreased numbers. Did I mention staying together?

7. You win. Eventually.

Narrative: I was the puller mentioned above; I pulled him away from the main body through a bomb. It worked; he took damage. Not enough to matter. Random orbs and an act of senseless hostility from Null against me led to the chain of events referred to above. After that party wipe (our third), we all ran back to find Null once again fully recovered with his beginning shield up and running - square one. By the time we beat him (another wipe was involved), one member of the party had only her skirt left and I had nearly worn out a second full set of armor. Notably, the Guardian, who stayed with a couple others at all times, suffered only four pieces of damaged armor. Have I mention how important it was to stay in a close group?

The above tactics evolved somewhere after the first party wipe in my next group to attack Null. These lessons are paid for, you may as well use them!