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Similarities: Non-blood related sibling love, based on a 10 volume manga, happy ending.

Minato is a university student and has a fear of germs. She isn't interested in looking pretty. She lives with her stepbrother Toru, who is her stepbrother from her mother's remarriage. Meanwhile, Toru is handsome and a player with the ladies. He doesn't resist women who come on to him and he doesn't stop women from leaving him either. Minato is uncomfortable with Toru and his ways with women. They are the same age and attend the same university. They have an agreement, where Toru will not approach Minato within 2 meters when they are outside.
One day, due to her friend’s request, Minato puts on make-up and wears her friend’s high school uniform. While she is out walking in public, she happens to meet Toru. She unexpectedly lies to him about her identity and tells him that she is a high school student. Toru falls in love with her at first sight.

Both dramas are based on a high society, from what I noticed- Show Window: The Queen's House is less focused on academics as The Penthouse but both dramas are focused on stepping over others and cheating to become the richest and top in the society. In the Penthouse, everyone is obviously neighboring in the penthouse with people who will turn on you anytime for social gain, in the Show Window: The Queen's House- they neighbor in a "rich society only neighborhood." In both dramas, there will be a mystry murder that happens in the very end but is also the opening of the drama in the first episode as a flashback which keeps us guessing who the murdered person is and who the murderer is. In both, the wife is nice to the mistress, but that doesn't stop the mistress from being jealous anyways and doing anything to ruin the wife and steal her riches. In both, the husbands are trash and are only married to the wives to steal their riches and company. Very similar vibes. If you enjoyed The Penthouse, you'll definitely enjoy this.

In both dramas, the husband will be married to a woman and also have a mistress, he'll pretend to be devoted to both. The mistresses in both dramas will approach the wife and pretend to be friends with them. In both, there will be a mystery murder. The vibes and society are also very similar. If you liked high class, you will like Show Window: The Queen's House

In both dramas the female protagonist rarely withdraws from picking a fight about the injustices she encounters in the office. The guy is the timid one and often is viewed as someone or too angelic or as someone who is just too weird.

Both are about two people who may have feelings one for another. Both works at the same office. The guy work for the company for a longer period of time, while the girl is a newcomer with a omplicated pasts about her relationships and previous jobs. The guy is trying hard to suppress his anger towards his co-workers and is often walked over by them... The girl is the one who fight for justice.

Both shows revolves around three interns (two guys and a girl) who enter a company at the same time... and their young boss. The female intern starts raise her voice about the injustices in the company and drags into the fights her co-workers. She and her boss starts to develop feelings one for another.

A number of topics, is very similar to "Dangerous Drugs of Sex".
Sexual assault, rape, grooming, the victim learning to accept the assault and romanticization of former sexual abused victims.

Both have a starring female character. In 'Find me if you can', the 3 male characters like the main character, while in 'Boyfri3nds', the 3 male characters are her 3 boyfriends. While 'Find me if you can' is mostly focused on a darker topic- stalking, it also has a surrounding romance and comedic plot, while 'Boyfri3nds' is mostly focused on romance and comedy.

(SPOILER: There is a slightly darker plot-twist).

Both are mystery-thriller dramas and they both have an 'investigation' to find the 'culprit' behind the act. 'Rumor' is somewhat darker than 'Find me if you can' (which has lighter moments). Both dramas are based on real-life topics: 'Find me if you can' is based on stalking and also showcases bullying. kidnapping, manipulation. While, 'Rumors' is based on rumors (obv) and their effect on people, being a victim of workplace bullying and judgement.

Unproblematic and mature love story
Everyday life and cute romance
Follow the lead through years
Incredible chemistry between the leads
The give the same "good/romantic" vibes

Both are contemporary hero shows, that aired around the same time, focusing on a pair of characters - the Minato brothers in R/B and the "best match" guys in Build.
There are also fourth wall breaking "previously on" segments for both shows.

The biggest difference, at least in my opinion, is that Ultraman R/B has multiple, actually well-written female characters. (And it also does not have a 29-year-old man/19-year-old woman relationship.)

both dramas are supernatural fantasy that deal with curses! mirror deals with a girl whose cursed by love. anyone she loves or who falls in love with her, dies!

both are supernatural fantasy that deal with curses with strong female protonagists whereas mystic deals with a 2000 year old curse, deals with a 5000 year old curse of a goblin whose curse can only be broken by his bride who will also cause his death!

both dramas are supernatural fantasy that deals with curses!
both have strong female protagonists that are cursed! mystics cursed owner lady has been cursed.over 2000 years and has to perform or rather help like 1000 souls in order to break the curse. In mirror the girl has to light like a 1000 candles to break her curse but the evil shaman that created the curse tries to blow out the last like 20 candles using dark magic!

both fantasy dramas deal with supernatural curses that with strong
single female characters whose both cursed! hotel del luna owner, whose been cursed.for over 1000 years that can only be broken if she finds true love but first she has to let go of her 1000 year old resentment of the betrayal from her first love! whereas mirror of the witch aka secret healer has been cursed over 5 years and anyone who falls in love with her or that she falls in love with , will be cursed !