It was no secret that Rhal, Asch's brother and the greater heir to the throne, was a moron. He only cared about war, yet somehow managed to court himself a wife.
Meanwhile, Asch knew the proper rituals, old they may be, and remained alone. Lady Grandma regaled him with endless talks of how she courted her late husband when Asch was young and unmanageable.
He retained some of the knowledge passed down, even years later. How it translated to human affection was a mystery to him, but it had to be similar. That's why, when it came to courting his human in the human realm, he devised a careful plan with his knights to woo you.
First came the show of claim, an act to make other Daemos back off so he may begin courting. That resulted in multiple spars happening in your living room. It was in shambles by the time Asch had finished challenging each of his knights. He didn't know why you were so bothered by it.
Next, a display of magical prowess. He didn't have much magic in his reserves, and with no way to renew it in your realm, he settled for something simple. He scorched his name on your bedroom wall. What? He made sure not to burn the whole house down! All you did was kick him out.
For the last task— Well, Asch didn't expect the violent reaction. He had offered you Daemos blood, his, of course. He didn't understand why that didn't work either. Should I put more in the vial? He had run out of courting methods.
The only thing left to do was direct confrontation. Asch burst through your door. "Human!" He waited until he had your undivided attention before speaking, "I have done everything in my power, yet nothing pleases you!"
You expected arguing, more shouting or fire, but Asch simply lowers himself onto one knee in front of where you sat. He looked down, ashamed of his failures at proving his worth, reduced to this desperate mess. "Tell me what to do to make you mine." He willed the last word out, bitter on his tongue. "Please.."