You can use the tight spaces between mobs and walls to deal damage. Therefore you want to bring mostly Bounce monsters. You might want 1 Pierce monsters to grab hearts or to proc allies' Bump Combos. There are both Damage Walls and Warps in this stage. Warps come out every even number of Turns and Damage Walls come out every odd number of Turns There are Light Specters that will lower the DEF of enemies by 3x to make them defeatable. Dark Specters will lower the ATK of enemies by 1/3. Focus on them on every stage to give you an advantage.