I'm looking for a manga that is mostly focused on the 'Revenge' aspect, (not a subplot). I'm already familiar with the more popular ones (like Berserk, Monster, Ouroboros, etc) so looking for something new and maybe lesser known. Thanks in advance!

It's been a while since I read it, Skyhigh: Shinshou maybe? (and it's numerous sequels/prequels)
I also remember Jigoku Shoujo (although I only watched the anime) which was about revenge too.

Cool, I'll check those out - thanks for the suggestions!

What about Old Boy? There have been 2 live-action movies adapted from the story, but the manga itself is rarely mentioned. If you like revenge stories, it's definitely the first that comes to mind. If you have the opportunity to check the korean movie, I can also highly recommend it.

Seizon - Life is also pretty good. It's another seinen story like Old Boy, with an old man as protagonist.

I had no idea that Old Boy was adapted from a manga! I love seeing the differences between manga/movie so I'll have to give it a read.

Seizon - Life also looks like something up my alley - thanks for the suggests!

Dendrobates
6 no Trigger
Ayeshah's Secret
New York no Benkei
Conductor
Chess Isle
Dear Boy
Duds Hunt
Dämons
Fly, Daddy, Fly
Fukushuu Kyoushitsu
Zenaku no Kuzu
Hammurabi Court
In Full Bloom (YON Jae-Won)
Innocent W
Kokuhaku
Kisshou Tennyo
Kangoku Jikken
Misu Misou
Number
Redrum 327
Sasori
Save Me
Tantei no Tantei
The Clock Workers
Akusaga - At first it'll look like the revenge is a subplot, but it's really one of the major driving points of the story. Houkago is similar.

Not really "lesser known," but figured I'd mention them anyway:

Banana Fish
Freesia
Kurogane
Kurosagi - The Black Swindler

Nothing more to add from manga that are focused on the revenge aspects, but a couple of Korean webtoons which are and are both very good.......Hanged Doll and Living with One Leg.

Good luck 🙂

Wow! That is a huuuge list! Thanks so much for writing all that out - I have so many options to read up on....woot! I really appreciate that you have several genres in the mix.

@svines85
OOoo, love me some good webtoons - reading goes by so fast with them. The synopsis of the Hanged Doll sounds very spooky and intriguing - I'll check them out, they both got some very positive comments! Thanks!

Inochi is a good revenge manga too. Shoujo but really gripping.