I’ve defeated the final boss in a very cheesy way (Babarian Tank with a lot of Damage Return).
Now I have a hard time even getting some money in the castle of New Game Plus – is there some way to return to the old “easy” castle ?
No, you cannot return to the original ‘easy’ castle.
However, if you find NG+ difficult: Equip grace runes.
Grace runes lower the level of the monsters making them easier to kill.
In the early levels of NG+ grace runes also turn the tier 2 enemies back into thier tier 1 form. This can effectively turn the castle back to it’s ‘easy’ form for a while.
Source : Link , Question Author : Yalla T. , Answer Author : Colin D