| Paradox |
Nightmare (SR) is an enemy introduced in the Collab Scenario. She's summoned with the Château des Romances, and is a regular enemy in chapter 8,9,10 and 12. Like all Nightmares, she can only attack and be attacked with pleasure, and ignore any pleasure barriers.
Strategy
The infamous gimmicky enemy of the collab, they are actually more annoying than threatening. Since only pleasure attacks work and in equal level on both ways, your option to deal with her are extremely limited. You have to keep most of your active party with members able to dish out pleasure damages, as you will simply be forced to flee otherwise.
At equal level, they have extremely low HP compared to other enemies. If you have a great party member to deal pleasure damages, focus on them first as they will fall extremely fast.