Duay Rang Atitharn (2018)

1. Two lifetimes for FL
2. There is a 20ish years age gap.
3. The FL reincarnates after her death as a stronger person with magic powers.
4. Both have a mystery to find out who killed her in the past life.
5. Both have ML being faithful to her since her death in her past life.

1. Reincarnation
In "Duay Rang Atitharn" the FL dies and gets reincarnated.
In "Kor Kerd Mai Klai Klai Ter" the ML gets reincarnated.

2. Age Gap
Both the partners of the dead FL and ML in each drama are still alive and much older than 15+ years.

3. Search to find the reason for death
In both dramas, the characters then search to find why they died (KKMKKT) or who killed them (DRA)