Guilty Akuma to Keiyakushita Onna

They are both revenge dramas. It is pretty much the same story, only with a female main lead.

They basically follow the same theme: revenge for family. And both have a little bit of romance in.

Both dramas have leads who seek revenge for being framed. There's also romance thrown in. Also, lots of people die. The endings of both are sweet but tragic.

The story concept is practically identical and the characters in both are amazing.

He Fei's wife, Li Mu Zi, disappeared mysteriously during their wedding anniversary trip. While he was searching for Mu Zi, she appeared again out of nowhere, but he insists that the strange woman in front of him is not his wife. Lawyer Chen Mai gets involved in this bizarre case, and more mysteries slowly emerge.

Revenge Mystery Violence combined to form a dark thriller with one good guy detective on the side to balance things out

Both dramas focus on revenge and feature an antihero. Also, the lead "good" character falls for the antihero.