Both main characters have somebody they wish to protect and are willing to risk their lives in doing so. There are sci/fi elements mixed into reality and have very heavy undertones of gayness/touchy-feely friendship that makes you go uwu. There's also quite a fair bit of action and government manipulation going on.

They are similar in how the plot revolves around two brothers; one good, one bad. The 'good' brother is the one who aids the police in solving crimes, whereas the 'bad' brother likes to create chaos and drive the police around in circles trying to catch him. Both shows have the good brother trying to turn the bad brother over to his side, never giving up hope that there is some good left in him. Both involves mystery, murder and action.

With 'Hello Monster' however, the older brother is the good guy.

Although in Guardian the gay storyline is muted (in script, the visual language makes up for it heavily) Ossan's Love is similar in the aspect of the storyline revolving around the main character falling for another guy.

[There are no supernatural, or mystery elements in Ossan's Love]

Both main characters have a special supernatural ability which enable them to solve a crime. They also partner up with a detective who's hotheaded when it comes to solving the case.

List of similarities:

- The protagonists of the movies wield katanas and have a tragic past. T
- Share the actor Yoshizawa Ryo.
- Action scenes

[this recommendation includes the Rurouni Kenshin movie trilogy]

Both movies are adapted from anime/manga and involve action sequences, samurai and a hero with a scarred past.

A list of similarities:

- Bromance (duh)
- Strong fantasy elements
- (some) strong female characters that can kick ass
- Action/mystery
- Characters have magic
- Two male leads have a hidden past that is not revealed until later in the storyline

The similarities between these two dramas are of course, Rain. In both he plays characters that aren't purely good. They have ambiguous morals and do things that would land normal people in jail. The stories also have many twists and turns that might leave you dizzy if planning a binge watch.

Plus they're both crime thrillers.

Both dramas have mystery and great chemistry from the cast. Mystery features strongly in both, although there is a lot more action in Guardian than I Remember You.

* Main leads have a past relationship which one of them has forgotten about.

The hosts are sent out to complete the storyline given to them and have to act out their 'characters'. Each show also has a member from EXO.

Both main characters somehow transport themselves through time by an accident involving death. They don't know whether what they're experiencing is reality or not and face trouble settling into the culture.

Both dramas where the main lead will go to great lengths to get his revenge. Includes manipulation and death.