Both Damage Walls and Gravity Barriers are plentiful throughout the quest. Bring monsters that can deal with both gimmicks if possible, but lean towards Null Damage Wall monsters with strong bump combos otherwise. All enemies in this quest are Water, so bring as many Wood monsters as possible. Okita Soji's Mech Slayer L ability will do a ton of damage to Mech units. Make sure not to bring any. The boss stages have a powerful X Laser that comes out from Okita Soji's head. Try to keep some monsters away from the top of Okita Soji and out of the X Laser.