-Both the male leads are immortal.
The male lead in the drama is a gumiho who is about a thousand years older than the female lead,the female lead is smart and intelligent and tries to find out about male lead's real identity.The drama is fun to watch .There are various twist and turns and also new devilish characters keeps on appearing throughout the drama.So basically the drama is filled with suspense,romance and supernatural/mythical beings.

-active participation of the female lead in the investigations in both dramas.
-there is humour in both the dramas.

-Both the male and female leads disliked each other at the beginning of the drama.
-Both the male leads are arrogant and rude but also adorably childish.
-There are cute jealousy scenes in both the dramas(Mainly the male leads get jealous in both the dramas)
-eventually the male and female lead fall in deep love.