Cornelia is an antagonist from Fire Emblem: Three Houses and Fire Emblem Warriors: Three Hopes. She is a powerful mage in the service of the royal family of the Holy Kingdom of Faerghus. Cornelia was once a researcher studying in the Adrestian Empire. Shortly after Hanneman left the Empire and was given a position at Garreg Mach Monastery, Cornelia also left and was hired by King Lambert to go to the Holy Kingdom of Faerghus to put her knowledge to good use. She was given top priority to improving Fhirdiad's infrastructure and was able to end the epidemic that plagued the Kingdom, being praised as a saint. After she ended the epidemic, one day Cornelia had a sudden shift of personality. Whether this is her true personality and she is from Agartha, or she was killed and replaced with an agent of Those Who Slither in the Dark is left ambiguous, but since that day she is only loyal to Those Who Slither in the Dark and doesn't care for anyone else. Despite people noticing this change, she was still trusted and the king appointed her a high post as a mage in service of the royal family. When the second Queen Consort Patricia's daughter, Edelgard, was taken away by Those Who Slither in the Dark, the desperate Patricia turned to Cornelia and said she wished to see her daughter again, no matter who or what she had to sacrifice to do so. Cornelia claimed that the one truly keeping Edelgard away from her was King Lambert, and then said she could make Patricia's wish come true at the cost of the king's head, henceforth starting the Tragedy of Duscur. Cornelia also used a young girl named Hapi in magical experiments related to the girl's mysterious Crest of Timotheos and its abilities. She had befriended the once-street urchin in order to get her trust before completely shattering it via first offering her good housing and food, then making her a guinea pig. The results of Cornelia's experiments resulted in monsters being drawn to Hapi whenever she sighed. Patricia was indignant towards Cornelia's treatment of Hapi and supposedly considered exposing her experiments, before she disappeared during the Tragedy of Duscur. Cornelia was once a kind woman, who was willing to cure the plague of the Kingdom. Currently, Cornelia is a power-hungry woman who is more than willing to claim the throne for herself, even if it means murdering Dimitri's uncle and framing the former for her crimes. Furthermore, she is a self-serving tyrant, as she was willing to given her territory to the Empire. However, it is strongly implied that the real Cornelia was killed and replaced by Those Who Slither in the Dark, as several people note how her personality and behavior changed quite suddenly and with another member of Those Who Slither in the Dark referring to her as 'Cleobulus' (Note: In the English version, Thales refers to Cleobulus as 'he', but in the Japanese version no conflicting gender is given). In regards to impersonations, this much is also said about Volkhard, Tomas and Monica), and at one point after the time skip, a merchant wonders why she has imposed ridiculous levels of taxation on the parts of Faerghus she rules over, pointing out that it makes no sense to drain a region so completely if they intend to keep making use of it as a conquered land. Dimitri furthers that argument in Three Hopes by pointing out to her that if Cornelia really wanted to destroy Faerghus all along, she simply had to fail in curing the plague, with her answering that it was "another lifetime completely". She's also considerably pragmatic, as when Dimitri's return inspires uprisings among the Kingdom citizens, Cornelia refuses to send troops to suppress them not out of any sense of mercy to the people, but rather because she knows she has to confront Dimitri with every soldier she has and can't afford to send any elsewhere if she is to have any chance of winning. Cleobulus, just like the rest of his fellow Slithers, is a cruel and sadistic person, who personally causes pain on those who he torments, such as Dimitri, often mocking him and revealing the truth behind the tragedy all just so he could enjoy seeing the despair on his face, and Hapi, whom was tortured and experimented by the sadistic imposter. He's also considerably pragmatic, as when Dimitri's return inspires uprisings among the Kingdom citizens, Cleobulus refuses to send troops to suppress them, not out of any sense of mercy to the people, but rather because he knows he has to confront Dimitri with every soldier he has and can't afford to send any elsewhere if he is to have any chance of winning. She also has a sweet mocking side to her as she enjoys watching allies feel betrayed and can have a mock motherly side. While Cleobulus' true appearance is still unknown, he is presumed to be a man given Thales used male pronouns to address him. He disguises himself as a rather well-endowed woman with a large bust and a pink shoulder length hair and a rather seductive eyes with light green irises. His attire mirrors those of the nobles of Holy Roman Empire or at the very least, an eccentric radio personality who presented the Eurovision or a wicked witch of the forest. He wears a golden crown-like headband with light green gems, a maroon red collar with little hexagonal gems tied together like a circle and a key like necklace attached to said collar, a dark red strapless form fitting dress with a maroon red lace-trimming, a combination of maroon red and orange feather boa as his dress shows a ridiculous deep cleavage. His breasts are quite large. In addition, he also wears a golden triangular like belt with 4 hearts hanging to said belt and to top off his very beautiful yet stunning appearance like a goddess from fantasy world, he sometimes reveals a smooth like legs beneath his skirt and wears a black heel shoes. Its still unaware if this is the real cornelia or if she was replaced but its strong implied this is cleobulus but it is still unknown.