Oh, man, I am hooked to both.
Seon-Deok Yeoh-Wahng (선덕영왕) is about an ancient female Queen of the Silla Dynasty. Queen Seon-Deok is known to be the first unifier of ancient Korea.
In the drama, Seon-Deok is Deok-Mahn, a young girl who wasn't aware that she was the twin sister of a current princess of Silla. Pretending to be a boy, she befriended who she'd find out was her twin, and was conscripted into the army.
So far, at episode 22, it's been revealed that Deok-Mahn is the twin sister of the princess. The reason why she was sent away when an infant was that during that time, there was a stigma towards twin daughters. Due to superstition, it was considered bad luck or a bad omen. That's why the princess having a twin was kept secret, even from the princess herself.
The drama is awesome so far, or at least addicting.
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Yureka (유레카) aka ID_Entity is pretty interesting as well. It is a Korean manhwa (manga), that began in 2000, about MMORPGs. Just the recent volume (volume 31 in Korea) was terribly depressing. In brief: Poor Piriyang.