After a cosmic accident lands her in another world, Jiwoo Seo is resigned to living as a whole new person. She has spent the past five years purging her new world of demonic energy as Akarna, a being who must sacrifice her blood and her freedom for the empire. But when the man she loves gets engaged to someone else, Jiwoo flees from her gilded cage. Rescued by a stranger from a clan of beautiful, otherworldly men, they concoct a plan to keep her safe—by having her marry them all. 15s6a
39 Chapters (Ongoing)

I normally stay away from male/female harem but this one I read out of curiosity and got hooked. The FMC was isekai'd, brainwashed by continents religion that she was some sort of messenger from God and they bled her to heal themselves. Made her as ignorant as possible until the helped her. She lived and survived clinging to the 's love only to be told that he's marrying another woman.
I highly recommend reading the manhwa and novel. The novel is already completed.