Obsidian, the daughter of Lady Rhea, had been kidnapped. Nobody knows lady Rhea had a daughter exept for a few people. In the lab the kidnapper brought her to they use her for experiments to get her in her 'true form'. And most of the experiment are torture... She nows that nomatter how strong she is she can't defeat them on her own. So she makes a vessel to get help. She kinda is the vessel. Trying to get people to believe and trust her, she falls in love. (I don't own fire emblem three houses or most of the characters)