This setup mainly relies on the Counter skill of Landsknecht, force skill of Protector and your luck. There are few things to prepare beforehand.

• 1 Protector (must equip a Shield and tough enough to survive 29F mobs' attack)
  
  
• 3 Landsknechts (each of them must be at least level 19 so you have enough skill pts to learn Lv5 Counter)
  8 pts to Sword Mastery + 8 pts to Axes + 5 points to Counter = 21 pts
  
  
• Any adventurer that helps you to kill mobs on 29F (personally I have a gunner on my team to help killing mobs on 29F with his Lv5 Ricochet skill)

5 Adventurers in total with 3 Landsknechts upfront and the remaining 2 in behind as follow:


*Counter 1,2,3 = Landsknechts

• 50 Axcela (Sets one's spirits ablaze, raising the Force meter by 30)
  
• 3 Nectall (Nectar-dipped plants that revive all with low HP)
  
• 1 Ariadne Thread (Thread used to return the party to town from the Labyrinth)

• A shield for Protector (you can't use the force skill of the Proector without a shield equipped)
  
• 9 Fate Beads (LUC +20, equip 3 Fate Beads for each Landsknecht that would greatly increase the Counter rate)

Once everything mentioned above is prepared, it's time to head to the Labyrinth. Warp to the Geomagnetic Pole on 30F and take the stairs to the left to go back to 29F first.

Before encountering Ur-child, you need to make sure the Force meter of your Protector is MAX otherwise you won't be able to use his Force skill on the first turn of the boss fight.

There is no random encounter enemy on 30F so you need to go back to 29F to charge up the Force meter of your Protector by using Axcela. When you are on 29F, just encounter any enemy (Cactlord is recommended becoz relatively easier to kill).

Enter the battle, use Axcela on Protector to charge up the Force meter. Once it's full, make sure your Protector is still alive and kill the enemy (just remember don't escape becoz the Force meter would decrease for doing that). If any Landsknecht dies in the process, just use the nectall you bring to revive them after the battle.

Now head back to 30F, create a quicksave before entering the boss room. Make sure your team formation is right and have enough axcela.

When you encounter the Ur-child, those 3 Landsknechts upfront keep spamming Axcela on the Protector and your Protector just have to spam his Force skill to protect the whole team every turn. When the boss hits your Landsknechts, they have a chance to deflect the damage back to the boss and it can deal up to 10k damage per hit. If you're lucky, you can kill the boss in just a few turns. If the fight is over more than 7 turns, just reload your save file and try again to prevent losing too many axcela.

Ur-child has 25000 HP, few Counter should be able to take it down. There is a 100% drop rate of an item called Eden Apple after defeating the boss and it sells for 100k en. Once you kill the boss, head back to town to restock and go straight back to the Labyrinth becoz it respawns every time you exit and enter the Labyrinth. So you can grind it as much as you like.

EZ

-Fin-