Although people tend to assume he's conceited and sadistic towards the person of his affection he actually does have a soft side. A soft side that he shows to no one else except for you. Why? Because they're not worth his time unlike you. He literally couldn't care less about the others. You won't even know he's so madly in love with you or obsessed with you for that matter he's really good at masking his feelings of mad love and obsession for you. By the time you realize his tendencies towards you it'll be too late

At first he hated you. He hated the way you talked and smiled, and you were always around those 3 incompetent people in all of Hogwarts, the so called Golden boy of the Wizarding world with the blood traitor Weasley and the mudblood Granger. He despised the way you laughed whenever someone told you something, if anything he felt like he should be the one to make you laugh. He's immediately appalled he'd even think something like that and he's furious at himself for thinking something like that about you. He didn't know why he felt that your opinion mattered so much and the fact that you were constantly on his mind irritated him further

He isn't the type to bully you in order for you to notice him. He does his work silently from the shadows and stalks you all the time. Blaise is also a logical person. Sooner or later he'll know he's falling in love with you and even though he's a bit mad at himself for it he comes to terms with it and accepts his feelings for you. When you got berated by Snape for accidentally mixing the wrong ingredients during Potions, he did feel bad when he saw tears prickle your eyes. You tried to wipe them away but he noticed it and he wasn't that heartless to make fun of you crying. He hated himself for having a soft spot for you. Someone next to you whispered how he could tutor you at potions and when he put a hand on your knee, unexplainable rage and fury coursed through his veins and he felt like using the most powerful spell on that git for daring to even think of touching you with his filthy hands

"They already have someone to help them with tutoring now mind your own bloody business unless you want me to teach you how to mind your business'' snarled Zabini and death glared at him as the other dude scooted away from you. You looked at Zabini in surprise and he had a calm and stoic expression on his face as he continued to stir his potion. Then he wrote something on a bit of parchment and handed it to you. When you opened it, you saw the words 'Library after class' and you pocketed the note. After class was done, you headed for the library where you saw Blaise sitting at one of the tables there. "How did you get here so fast?" you asked him as you set your bag near one of the chairs. "I walked'' he deadpanned and continued "Professor Snape talked with me before class started to tutor you in Potions since you're absolutely deplorable at it'' and you spoke "Yeah, like I need another reminder of that'' and he continued further "But since Malfoy has other things to do, looks like I'm stuck with you. And I will make you get a better grade in it'' he said and you didn't know whether to feel scared or happy when he said that

He explained some concepts to you and when you had trouble memorizing where some ingredients of the Sleeping Draught were found, he handed you some of his flash cards and told you that you could use them. When you thanked him, he spoke "Don't be too carried away, I will ask you where they are found later on'' and you gulped nervously. For 2 weeks this continued, he was actually really patient and calm with you never really losing his temper at you. Of course he would stare at you disapprovingly when you made a mistake but when there was something you didn't understand, he was patient with you. Once you got so frustrated with not being able to understand something you actually had tears in your eyes. That was also the day you barely got any sleep as well. "Ugh, I guess I'm too stupid to understand this'' you sniffed and ruffled your hair in frustration. He looked at you and spoke "Stop crying and don't worry. You just need a bit more practice and sleep. We'll continue when you got enough sleep'' he said and you refused but he made you go back to your dorm and get some sleep

Did he leave you alone after that? No, he used a spell to watch you sleep and the way your chest rose up and down when you breathed made him relax. He knew this was completely wrong but he didn't care. He just needed to see you sleep, he can't have you ruining your health, he cares for you. He's like a fussy mother hen, always making sure if you're having your meals properly and getting enough rest. And if you aren't he's there to make sure you get your lifestyle back in order. After a few sessions of him tutoring you, you finally aced a surprise test which Snape decided to conduct and needless to say he was actually impressed with your work. "I normally don't say this but your work was acceptable this time. Maintain it like this'' said Snape as he handed you your paper with an 'E' because that was the highest he was willing to give anyone in his class

You stared dumfounded at your paper, unable to believe it was yours. You couldn't believe you got something like that so you smiled and thanked Blaise. When you did so, he felt like there was something wrong with his heart because it started beating erratically. He invited you for some Butterbeer at the Three Broomsticks and you agreed. Blaise and you went to the Three Broomsticks after classes were done for the day and you both hung out with each other. Blaise liked being near you and you found out he had a soft caring side that he hid from everyone. You found this out when you accidentally spilt some Butterbeer on your robes and he offered to clean it up for you. Then he handed you a box of Honeydukes sweets and asked you go out with him and you were surprised but happy so you said yes. He kissed you after you consented and it felt like a magical kiss. He felt on top of the world and after you both went back to the castle, he kissed you goodnight and dropped you back to your dorm as he watched you go up the steps

He went to bed, thinking about you and now that he had you for himself, he'd never let you go. It was only a matter of time before he 'saved you' from all the darkness of society in the Wizarding World by taking you for himself