Lucia Bellcourt was the shepherd in Game 4, a young lady of 14 or so who is an avid collector of rarities, be they human body parts, keys, bugs, or other. She has a rather lonely lifestyle, with a comatose brother, dead infant sibling, too-busy absent father, and ill and absent mother. She's grown up as quite bratty, very intelligent, but not terribly focused; she dropped schooling the moment her parents' attention was off her, and studies codes and cyphers for her own entertainment. She clearly relies a great deal on her butler, Mr. Sidney. Although it's clear to the players that her house was haunted, Lucia denied the possibility and, whenever anyone brings up the hauntings, tends to go into hysterics; likewise, when people try to imply her brother as a ghost is trying to communicate. She seems eager for friends among the players but overly cautious regardless.
In game 5 she used the players to get artifacts in the hopes of getting her hands on the Sword, which was ultimately successful. She also drugged them and stole some of their cool stuff.
In game 6 she put the players in Bastien's soul in the hopes of getting the last 30% of the soul, which he sealed and died with the secret; a part of the sword stayed hidden in his soul to try to keep track of itself. This was less successful; Sera ate the last part of the sword, Bastien challenged her (who turns out to be his great-something-great-granddaughter), the players drove Asmodeus out, and she broke down and attacked them with the sword.
In game 7 she had been possessed by the Sword and was straining against its mental corruption. She had again kidnapped Bastien (as she is wont to do) and was going to use him as a familial sacrifice to bring Asmodeus back, but is eventually convinced to let him go. The Crow want her crimes on trial, and had tried to take her brother as collateral -- eventually they took her father instead. Lucia, who gave up the Sword as part of her attempt to keep her family safe, is now attempting to bond with her brother again and grow stronger so they can work together to clear her from Hell's charges and retreive their father.
In game 8 she went on trial, and the charges were (fairly swiftly) dismissed. But most of Hell sure got a good look at her...
Lucia has a great deal of difficulty feeling certain emotions such as regret, but despite that has a strong guilt-complex, and is extremely self-centred. She tends to believe others are going to turn against her even if she wants to be friendly towards them, and so turns on them first. She cries easily and gets angry easily, displaying some hot-and-cold personality traits. She doesn't believe in a universal evil, per se, and views a lot of things such as other people's pain as unfortunate necessities. Despite this she is lonely and wants friends to care about. She has a very strong inferiority complex.
Mr. Sidney first appeared to the players as a polite and competent butler who managed Lucia's affairs for her, including arranging the game she wanted to do. He was competent in buttling, providing comforts, and cooking. As time went on it was clear he had a hidden sadistic streak; he took a dislike to Shuri, whom Lucia was flirting with and who made Lucia cry, and that night he both gave Shuri a worse meal than the others and Shuri had a bad dream of being tortured by Mr. Sidney via evisceration (Kaname drew fanart). He also showed a possessive side, controlling situations where people were trying to get favors from Lucia. Those in limbo discovered that Mr. Sidney had demonic powers of great strength, and by the last day he wasn't particularly bothering to hide it from the other players, showing more of a joking side (if with a poor sense of humor) and offering people gambles, including a game of 'spin the bottle' with Konatsu in which he extended his tongue all the way into Konatsu's stomach. :')
He reappeared in game 5, again playing the role of Lucia's butler, though it was revealed he was actually the demon prince Asmodeus. He continued to act as her aide despite this open knowledge and was generally unconcerned by the players' reactions to him otherwise. It also became clear at this point that the two of them had begun sleeping together sometime between the two games. Awkward...
In game 6 he aided her in the blood magic to summon and bind Bastien's soul; however, the players used his weakness - smoked sheatfish -- to drive him out, where he had an unfortunate run-in with a familiar Italian doctor... he has not been seen since.