Psychic Connection

Both share prophetic dreams.

The fifth episode with her guardian angel, he's aware of her at all times.

He has precognitive visions that mostly revolve around her.

Saw this a long time ago but I believe his alien powers enable him to keep tabs on her even when he's not physically there.

Male lead has telepathy that doesn't allow him to hear her exclusively but he does use it to read her thoughts quite often.

The candle flame summoning was a creative touch (maybe tied to Korean Goblin mythology that I'm unaware of?) and I liked that the birthmark let him hear her call if she was in life or death danger.