1. Lovelyz' 'Girl' trilogy part 1: Candy Jelly Love
Lovelyz debuted with a trilogy project under the 'girlish' theme, and kicking it off is their debut song (of course) "Candy Jelly Love". It's a sweet, innocent concept that perfectly matches their 'girl' concept.
2. Lovelyz' 'Girl' trilogy part 2: Hi~
"Hi~" is the second part of Lovelyz' 'Girl' trilogy, and the girls go a just a pinch less cheerful and a pinch more innocent for their 'girl' concept continuation.
3. Lovelyz 'Girl' trilogy part 3: Ah-Choo
Lovelyz kicks up the girl factor to the max in their cutest and most bubbly release of the trilogy, even more special as Seo Ji-soo finally joins the group to make it a full 8 members.
'Dynamite' from the single album 'Zelo's kicks off VIXX's 'Conception' trilogy (aka the Greek god series). The concept-dols start their series featuring Leo and N in connected roles that are further explained later on.
5. VIXX 'Conception' trilogy part 2: Fantasy
The second part of VIXX's 'Conception' trilogy is 'Fantasy' under the single album 'Hades'. The boys take the drama up a notch in both song and MV and continue Leo and N's story.
6. VIXX 'Conception' trilogy part 3: The Closer
'Kratos' is the final piece of the 'Conception' puzzle, and title song "The Closer" takes quite a twist as it reveals Ken as the master puppeteer behind everything.
The 'Lost & Found' set with the title song "All In" introduces MONSTA X's 'The Clan Part 2.5' project as well as the concept of the 'X Clan', introducing boys who are struggling in a dystopian society as well as Hyungwon and Minhyuk's eerie relationship.
8. MONSTA X 'The Clan' trilogy part 2: Fighter
"Fighter" is the title song to the 'Guilty & Innocent' set, the second part of the boys' 'The Clan' trilogy. "Fighter" continues MONSTA X's story from "All In" and also shows their escape from the grips of their world.
9. MONSTA X 'The Clan' trilogy part 3: Beautiful
The 'Beside, Beautiful, and Brilliant' set completes MONSTA X's trilogy and is the (confusing) conclusion to their 'The Clan' series.
10. G-Friend's 'School' trilogy part 1: Glass Bead
G-Friend kicks off their well-loved 'school' trilogy with debut song "Glass Bead", previewing a bright sound, a fresh image, and an amazing choreography. "Glass Bead" is the start of a beautiful love that the girls vow to protect
11. G-Friend's 'School' trilogy part 2: Me Gustas Tu
The second part of the girls' school series is their giant hit "Me Gustas Tu", which is a lot preppier and brighter than "Glass Bead". In the second installation, the girls hope for their love to take the next step.
12. G-Friend's 'School' trilogy part 3: Rough
In the last part of the girls' trilogy, the girls graduate from school and hope to become adults. They bring out a less innocent sound but keep their trademark vibe for the final part.
Perhaps the only idol group that could even attempt a 'ballad' trilogy, BTOB started off their unique project with 'It's Okay', where the vocal members got to show off their full prowess.
14. BTOB's 'Ballad' trilogy part 2: Way Back Home
Apparently 'It's Okay' wasn't enough to showcase BTOB's vocal abilities enough, and the group takes it up one more notch with 'Way Back Home', adding adlibs that even the main singer and lead singer have a hard time doing.
15. BTOB's 'Ballad' trilogy part 3: Remember That
The final part of the ballad trilogy is a spring carol that softens out the trio and ends it on a melancholy note. The boys went back to dance songs after this but definitely showed the world their voices.
BTS debuted with the first part of their 'School' trilogy "No More Dream". The trilogy tells the story of teens suffering through a strict society, and 'No More Dream' is the 'Dream' portion.
20. BTS' 'School' trilogy part 2: N.O
The second part of BTS' 'School' trilogy is "N.O", which continues the story of teens suffering through the hardened system. "N.O" is the 'happiness' portion.
21. BTS' 'School' trilogy part 3: Boy in Luv
The boys wrap up their school trilogy with "Boy in Luv", ending on a happier note with the 'love' portion of their trilogy.
22. BTS' 'Beautiful Moment in Life' trilogy part 1: I Need U
In what is BTS' biggest project that had been planned since before debut, BTS drops an MV packed full of hints and messages and lets fans start their journey down the most beautiful moment in their lives.
23. BTS' 'Beautiful Moment in Life' trilogy part 2: Run
BTS continues on with their story and bring even more messages (and a lot of confusion) as they continue to run down the most beautiful time in their lives.
24. BTS' 'Beautiful Moment in Life' trilogy part 3: Fire
It could be argued that either "Fire" or "Spring Day" is the final note on the boys' trilogy, but "Fire" is the official ending as the title song of their 'Epilogue' of 'HwaYangYeonHwa'.