https://www.mangago.me/read-manga/weak_hero/ it's a webtoon though but one of my favs
thanks for the rec but I alredy read it
(Warning: some may contain dark themes/images. Also, I haven't caught up with some of them, but as far as I know they don't contain any significant romance)
Kings' Viking
Kamonohashi Ron no Kindan Suiri
Shokuryou Jinrui
Shokuryou Jinrui Re (sequel to the previous one)
Vinland Saga
The Dark Magician Transmigrates After 66666 Years
Lookism
Death Note
The Boxer (tiniest amount of romance, but its so small that it doesn't really make a huge impact)
Hunter x Hunter
Phantom Tales of the Night
Bless
One Piece
Kiichi!!
Kiichi!! VS (sequel to the previous one)
To You, The Immortal
Eleceed (romance that is being very subtly and slowly hinted at in later chapters)
Juujika no Rokunin
Billy Bat
Jojo's Bizarre Adventure
Route End
Unhinged
Hi all can you, please suggest any good mangas which have a excellent plot but has NO ROMANCE. like for ex: polarity, a country of maestro