Vinum

Vinum is a succubus fought in the Collaboration Scenario. She comes from Succubus Prison: House of Lewd Demons with Nemea and Myusca. She's a cruel succubus that enjoys corrupting heroes. She is the boss of chapter 8.

Biography
She is first briefly seen at the end of chapter 2 when Kazuya runs into her and Nemea. She's intrigued by the fact that they managed to escape Myusca.

When Kazuya understands that Vinum is a succubus on a league of her own, she enjoys the perspective of tormenting him before she disappears to suck dry more villagers.

The party encounters Vinum again in a library. Luckily, she is too busy reading and doesn't want to be disturbed. The party is forced to sneak through a mess to not catch the attention of the succubus. However, when they meet her again after she feasted, she decides to start chasing them. She catches them back just as they're fighting Nemea, and Myusca soon join them again. Fortunately, the party is saved by the intervention of Magatsu, Lauratt and Rigeo as Vinum notices that they would take a risk they can't afford by fighting them.

When Myusca tells Kazuya that she got the Proof of Collaboration when she arrived, Vinum reminds her that she got it from her first victim who was supposed to be the hero of their world, which surprise the succubi as he was incredibly weak. The succubi taunt the heroes as they're now down to six, but Kazuya tells them that he's determined to find a solution.

The trio reappears in chapter 8 as Kazuya and his group are fleeing Fulbeua and Musette. They chase the party and force them to go underground. Vinum then teleports in front of the group, and engage them in a fight. After getting pushed back, Myusca and Nemea arrives as reinforcement to finish them, but a full fight blows out as Luka and his allies step in and rescue Kazuya's group from the Succubus trio. The situation becomes even more chaotic as Mysteltainn, Ogretooth and Executioner show up while chasing Lest and his companions. As they fight, Myusca ends up caught by one of Daimyokai's trap, and while she tries to break free, Vinum tells her to stop trying. The heroine accompanying Luka notices that both groups seem to be too wary of each other to work effectively, point upon which Vinum concedes. Eventually, the groups negociate the succubi' retreat and have Myusca give out the Proof of Collaboration to Luka before leaving.

They reappear during the banquet between the members of the alliance of the queen of dreams, as Musette is furious that they let the heroes go while they have their own agendas. Vinum remarks that while they will do everything to expand the "Land of Night", they do so for their own pleasure and not out of loyalty

The succubus trio tries to attack another village in chapter 12, but is then intercepted by either Eden, Zion and Gnosis on Alice's route while they're engaged in a fight by Lilith, Astaroth and Morrigan on Ilias'.

She can be recruited with her partners in the post-collab as they returned to Finoa with the plan to "play" with the heroes through trials that force them to have sex with their partners to reach them. Eventually, the trio fights the heroes and join them after being beaten, telling them that while they find the idea of fighting on their side fun, they hold no loyalty to them, so they shouldn't lower their guard.

She makes a short return as an antagonist during the Time Loop Event with her two partners. The soul of her victim, Toru, who was the protagonist of their world tethered to Luka and is responsible for the event that blocks the hero in a 4-hour long time loop. Luka is sent in their world slightly before the Collab events by Promestein to save the man and another victim. She will suck him dry if she meets the hero, although Luka can lure her away with a powerful labyrinth book and challenging her thirst for knowledge. When Luka and Toru successfully flee from their house, the latter returns, bewitched by the pleasure succubi offered him. When she shows up in the Yamatai Night Festival afterward, she asks Luka if he has "a good book to pass time", not so subtly refering to her knowledge of the events that transpired.

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

Attacks

 * Attack – One Foe, Physical Attribute
 * Instant Caress – 4 Random Foes, Pleasure Attribute
 * Four Star Strike Destruction – 4 Random Foes, Auto Hit, Dark Attribute, Death (10%)
 * World-Shattering Fist – One Foe, Physical, Death (10%)
 * Whirlwind – All Foes, Auto Hit, Wind Attribute
 * Moonlight Nocturne – All Foes, Magical, Lightning Attribute, Shock (10%)
 * Kiss of Death – 3 Random Foes, Pleasure Attribute, Horny (75%), Death (20%)
 * Succubus Ceremony – One Foe, Pleasure Attribute, Climax (25%)
 * Energy Drain – One Foe, Pleasure Attribute, Drain HP 500%
 * Demon Eyes of Climax – All Foes, Magical, Climax (75%)
 * Demon Eyes of Crushing – All Foes, Auto Hit, Dark Attribute, Stun(75%), Slow (75%), Real Battle only
 * Demon Eyes of Seduction – All Foes, Magical, Trance (75%), Chapter 8 Battle only

Chapter 8
The senior of the Succubus Prison trio is, as one would expect, a tough opponent. As usual for succubi, she possesses numerous status effects that can wipe out your team on their own, as well as more than reasonable damages. Using Magatsu with a charged attack is a high risk/high reward move as you're bound to remove half of her life, but are just as likely to end up stopped midway by a crowd control effect.

Using holy attacks is quite effective against her. Last, don't forget a loss can be replaced with another party member in a pinch.

Real battle
The final fight against the three succubi is a relatively tough one. All of them possess a large number of party-wide status effect, high-damages attacks, and ways to heal themselves if not the whole party. Without resistance to climax, losing your whole party in the first turn in a dangerous possibility. Their attacks aren't limited to pleasure and wind, which means that you can't simply hope to reduce this fight to a cakewalk by bringing resistances to both. Fortunately, as they have limited auto-hit attacks, evasion and magic evasion/reflection is a valuable defensive option.

Your main target should be Nemea. Between her disruptive wave and her mass mega heal, she is the biggest source of annoyance for this fight. She presents an unusual weakness to ice, but holy attacks have a bonus against all three, while earth damage is also quite strong, although it only does normal damage against Vinum. Setting combos over several turns is too risky to be worth it.