Yandere doesn't need to be the male lead, he can be second male lead or villain.
It can be Korean,Japanese,Chinese. 

King's woman (Chinese)- ML is a total yandere. Tried killing the FL's lover and forced her to marry him. 

Too late to say I love you (Chinese)

@jimochi   

- Jin Jiu Ling , a chinese drama with a villain being a yandere. 

- Scarlet heart ryeo, ml has yandere vibes.

- Well intended love , ml is a yandere.

-Secret , ml hated the fl then turned really obssesive. Chemistry between leads is really good.

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Did you try looking with the tag: Possessive Male Lead?

The second ML in The Eternal Love is Yandere, but I feel so bad for him still...