One is BL and the other M/F but both are have the themes of the ML waiting for the reincarnation of his love from ancient times, and the possibility of them coming back looking different while there's another person with the original face in modern day. Both have a cat shapeshifter who helps the ML.
This drama is a love story between Kataoka Sakuya, a grim reaper who comes to the human world for the first time, and Mochizuki Nayuki, a woman who lost her father at a young age and has devoted her life to raising her only remaining family—her younger brother. As they meet, they gradually come to understand each other, and slowly, they begin to fall in love. However, a fate that will dramatically change their lives awaits them both…
L, an angel who’s endlessly fascinated with the human world, gets into trouble when she unthinkingly saves the life of Han Shi Yeong, a man who was meant to die. To make up for her mistake she must guard him on Earth for one hundred days and keep him safe from Hwan, a death god who is required to collect his soul. Both supernatural beings must contend with the knowledge that whichever one of them fails by the end of the hundred days will be erased from existence, and the longer they stay on Earth the further their powers fade and the more human they become.
If you liked the first few episodes of Heartbeat, and the overall vibe initially, then you will like From Now On, Showtime. Heartbeat's strength was likeable characters, good acting and a great concept. But the writing was unable to fully flesh out the drama in the way that it deserved. From Now On Showtime has the character development, the acting, the concept and the writing is so well done. It delivers in ways that Heartbeat wishes it could have.