Gilgorn

Gilgorn is a boss from the game Succubus Rhapsodia. She's the boss of chapter 10 of the Collab Scenario, and the original lord of the Château des Romances

Biography
She's first seen in chapter 10, clearly annoyed that her castle has been invaded by Nightmares and wary that she's in another world. When she notices the party, she thinks that they're Nightmares here to finally take her down.

After beating her down, she relents and accepts to help the party to fight Nightmares, asking them why didn't they ask sooner, ignoring that it was the first thing they did.

When the party attacks the castle to get rid of Nightmares, she starts bombing the Château des Romances as it was planned with Rovissa. However, she ends up overwhelmed by Nightmares as she bombs the castle. Still, she manages to deal a great deal of damages before being incapacitated.

Once the story is complete, she remains in the 4th floor of the Château des Romances where she builds herself a reality barrier to keep Nightmares away. The heroine try to convinces her to leave, but she refuses. However, when the party beats Fulbeua, the latter gives a rune to Lauratt to allow him to break the barrier.

When the party returns to her, Lauratt instantly shatters the barrier, and after traumatizing the Demon Lord in a fight, she accepts to join the party if it means Nightmares will stop trying to pleasure her.

Monsterpedia entry
"A being who arrived from another world. Further Details are unknown."

Attacks

 * Hero Killing - All Foes, Auto Hit, Dark Attribute, Death 50%
 * Meteor Eclipse - All Foes, Auto Hit, Fire Attribute, Burn 10%
 * World Breaker - All Foes, Auto Hit, Galactic Attribute
 * Ruler's Demon Eyes - All Foes, Auto Hit, Poison 50%, Blind 50%, Silence 50%, Confusion 25%, Sleep 25%, Paralysis 25%, Death 25%
 * Strelitzia - One Foe, Auto Hit, All Stats Down
 * Strelitzia: Alda - All Foes, Auto Hit, Dispel Buffs

Strategy
Both of her fights are roughly identical. Only one of the drops changes. Since you have access to your whole roster, your options will be varied. Gilgorn has powerful auto hit attacks, a large slew of status effects and can act three times per turn. Her stats are also extremely impressive, and with her 990000 HP, she's currently the enemy with the highest number of hit points bar none.

She is EXTREMELY WEAK to pleasure attacks (300% damage) and related effects. If you have Alma Elma with you, she will turn the Demon Lord into her breakfast in a few turns with Lilith Orgia.

Alternatively, bringing in a succubus will make the fight just as easy. Any method of inflicting Trance on her before she can act, like Sexy Dance, will render her unable to act at all. It is pretty much a requirement for this fight, but one easy to fulfill.