Quest #107 Off the Record - Mirage Mahal (Gleeba)
Quest Requirements: Defeat 3 Infernal Armours with Pincushion
Quest Pre-Requirements: Level 15+ Paladin
Reward: Holy Mail and Holy Femail
This quest is given to you by Brunhild, the Paladin on the roof of the Mirage Mahal in Gleeba that gave you the Paladin Class Unlock Quest (assuming you've done that). In order to accept this quest you'll need to have unlocked the Paladin class as well as have a Level 15+ Paladin in your current group.
For this quest you'll need to head over to the Gerzuun dungeon which can be found northeast of Batsureg. From Batsureg travel north one screen then east one screen to find yourself in the Mt Ulzuun area. Gerzuun is in the northern portion of this area.
Inside Gerzuun you'll want to look for the Infernal Armour enemies (screen shot above) which are the enemies we need to defeat for this quest. Depending on your current characters your strategy for completing this quest will change drastically.
Basically in order for the Pincushion ability to deal damage to the Infernal Armour your characters are going to need very low defense and be very low level. Additionally you're going to want to have the Pincushion ability on every character in your party - otherwise this quest will just be super annoying and time consuming trying to get him to attack the right person.
If your defense or levels are too high for the Infernal Armour to deal significant enough damage to be injured with Pincushion then you'll want to take off all of your gear and try things that way. There's one more thing you can do to give yourself an even larger handicap... Use Double Up during battle to greatly lower your defense - I had to do this in order for the Infernal Armour to hit my level 14 naked characters hard enough.
The Infernal Armour only has about 120 health so I would recommend inflicting about 100 damage to it then using Double Up and Pincushion for as many rounds as Double Up lasts. Keep repeating this until the Infernal Armour destroys itself on your Pincushion.
Note: If you need to do a small hit to the Infernal Armour use the Hot Lick Minstrel ability. It only hits for 15 - 25 damage which makes it a great way to whittle down an enemies health.