Oh! My Emperor

Episode 11 (1x11)

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When Buk Dang-hyeok finds out that Nabi-bi is the lord of Ophiuchus, he becomes very angry and urges him to leave immediately. Nak Bibi is poisoned, absorbing her other superpowers and attacking Buk Dang Hyuk, but is struck by her sword and collapses. The Empress Dowager orders her to be executed, but the new king tells her that she is his wife.