ml love fl long ago at first sight, after he visited palace to ask for support because his land suffering from poor and drain, but the emperor refused to meet him, he accidently saw beautiful fl and he thought he never can marry her because her family is rich and his land is poor. Later he received the letter from emperor about marriage and he was surprised abt this, and he tried to find the way to solve problem in his land because he loves her and fears she hate this marriage because he cant provide her the life like in capital. So he went to fight with monster to find the source of problem. He got a lot of injure and scars due to that (fl never know about this).
OP basically said that he has no real power in the dukedom and since his land was poor, he has to go an fight all the monsters to get recognized. apparently the FL grew up rich so he wanted to give her those same luxuries.
SPOILERS ABOUT ML FROM NOVELUPDATES
ml love fl long ago at first sight, after he visited palace to ask for support because his land suffering from poor and drain, but the emperor refused to meet him, he accidently saw beautiful fl and he thought he never can marry her because her family is rich and his land is poor. Later he received the letter from emperor about marriage and he was surprised abt this, and he tried to find the way to solve problem in his land because he loves her and fears she hate this marriage because he cant provide her the life like in capital. So he went to fight with monster to find the source of problem. He got a lot of injure and scars due to that (fl never know about this).
OP basically said that he has no real power in the dukedom and since his land was poor, he has to go an fight all the monsters to get recognized. apparently the FL grew up rich so he wanted to give her those same luxuries.