Melissa is one of the four hirable adventurer's and Lucia's mistress. She's a dark mage who ruling some illegal black magic's experiences and business in Anvil.
Melissa were the firstborn daughter of the Holy Capital Villa's Pontifex, but got banished due to her white hair. She study black magic and become the Dark Witch. She were implicated in lot of Cursed Armor intrigues : since she studied Abaddon Parasite, she controled Lucia by put a Abaddon worm she made and transplant and Abaddon Penis on John who used him to submit Gloria and Trossi (and maybe Lilina and Sarah). She also have business with House of Love, working with them to do some experiences on some clients who uncarrefully sign a contract for testing products. And she got some relations with Mages who do some illegal business with her for money and advantages.
Finally, she met Lilina at the guild. When she felt Cursed Armor power, she were interested and accept to help her for some quests if she let her try some experiences on her. With this, she noticed she is a sucubus and do some experiences about it (who can change Lilina or Lucia statistics or give futanari spell to Lilina). When Lilina save Sarah, Seaclya told her to ask Melissa about divine power since she noticed that John divine artefact had similarity about Lucia's energy. Thats how, for a milion gold, Melissa talked to Lilina about Abadon parasite.
If Lilina get caught to Island Village, Melissa will bring a mage to take her and bring her to the Dark Witch who gonna remove parasite then do Lilina her toy like she did to Lucia.
Melissa is a selfish person. All she do is for her own interest. She's also passioned by dark magic and demoniac power : Succubus, parasite or some things like this picked her interest and she make a lot of experiences about it. Since she rule some illegal business, she have a lot of contacts for her needs : mage, John, House of Love employee, etc. However, she have no sexual desire : even if the cursed armor tried to influence her by raising her desire, she seems aware of this manipulation and acted like if she were submited by this power, but it was just a pretext to study Lilina's power. It were never said that she have sex.
Even she's the Dark witch, Melissa have some standard magic power, but lacking of strenght. Even her dark magic wont be really powerfull. he only interest is her sleep magic to gaining some time. She let Lucia do the job about fighting, it seems.
Robert : Robert hate Melissa for what she did to Lucia. Except this, we dont have real information about their relationship.
Lucia : Melissa make Lucia her playtool. She probably dont have any affection for her, but only interest for her research and her utility as bodyguard because of her great skills as warior.
Lilina : Melissa have a real interest for Lilina since she know shese a succubus. She want her as a toy she can study. But she have no affection for her, she just want her like a child want a toy.
John : We dont know how Melissa met John, but we know that he gained his divine penis thanks to Melissa who transplant it to him. Why and how, nobody knows. Maybe it was for gain John's favor. Since he were the Torres's Chambellan, he could bring a lot to the Dark Witch.