They both have the 'married to a person I don't love' trope. The second lead couple is similar to the main couple in my heart. Both princesses are titled 'naughty' both male leads are like the playboy nice type. Both are the first sons to the emperor but not the succesor.
Both dramas are Romance/ Historical/ Political
In both dramas there is a prophecy that two sisters are destined to marry the emperor, and this prophecy forces them to get entangled in political affairs and live in the palace.
Palace politics; multiple couples and people falling in love or marrying the wrong people first and then finally the right people. Much jealousy but also a strong sense of loyalty towards loved ones.
