Responses
https://www.mangago.zone/read-manga/to_deny_the_route/ okay it's prob not this i dont remember the ml having a curse....
I think you are looking for Fullmoon alchemist, by Dongjeon Banji.
beta
I forgot the title and this is bl
> MC is a mage and he makes potions, he is a commoner. Mc was trying to experiment with his newly made potion, the potion makes your soulmate appear(something like that)
> ML is a duke(something like that) and he has a curse.