Both are historical mini dramas in which the FL is an assassin who marries the ML in order to kill him. Both leads have a past connection which the ML discovers first.

Both are about an arranged marriage between two very different kingdoms, one of which is looked down upon by the other.

Both are mini dramas with a similar vibe, with the FLs thought of as evil and the MLs subservient to them but powerful fighters.

While different time periods, both are historical/mystery dramas with a similar vibe, and interesting cases. One lead is trying to resolve the tragic death of someone close to him, and the other is an orphan with a master.

Both are historical/mysteries dramas featuring bromances where the leads are often on opposite sides.

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One is M/F and the other BL but both are about the love story between a sweet, innocent robot and a somewhat withdraw human. Both robots are created as companions, with the creator objecting at first to the relationship. Both leads separate close to the end for several years, before a happy reunion.

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Same story, one is a movie adaptation, the other a tv adaptation.
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Both have the same actor and actress as the main couple.
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Both couples were in love, then ML seemingly betrayed the FL, harming her or her family. Years later, with ML married to someone else, they meet again, and he treats her cruelly while still seemingly in love with her.

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