Y/n Y/l/n was in love with Regulus Black, and everyone knew it. Most people didn't care about her crush. Sirius Black was an exception. Considering y/n was his best friend, and Regulus was his brother - he was not, in any way, okay with it.

Y/n walked down the hallway, her robe clutched under her arm. Y/n felt a tap on her shoulder so she turned around to see who it was. "Oh, um- Hi, Regulus." She stammered. "Y/n, hi. Look, I've been meaning to talk to you." Regulus sent her a sly grin. "You have?" Y/n asked, looking around to see if this was a joke set up by James. "Yeah. Listen, no one's in the Slytherin common room, so if you would like to... come chat with me now?" Regulus offered. "Sure." Y/n nodded.

The two made their way to the common room. When they got there, Y/n looked around. It wasn't like she had never been inside before. The common room seemed to look different when you weren't under the invisibility cloak.

"Come, sit." Regulus smiled, waving to the spot on the couch next to him. Y/n sat down and turned to face him. "So, why are you talking to me now?" Y/n asked. "I was just looking at you in potions and I couldn't help but notice how pretty you are." Regulus exclaimed, picking up y/n's hand with his own. Y/n turned her head to hide her blush. "And what about me? What do you think of me?" Regulus asked. "I think we both know what I think of you, Regulus." Y/n mumbled. "Yeah. But I want to hear it come out of your mouth. It's not the same when Barty tells me." Regulus replied. Y/n's breath hitched in her throat - they both noticed it.

"I want us to get close." Regulus continued. "And how do you want to do that?" Y/n questioned. "You're friends with my brother, correct?" Regulus asked, ignoring her question. "Yes." Y/n nodded. "Help me. I need you to... be my spy, I suppose. You can do that, can't you?" Regulus whispered. He knew all too well the power he had over her. "I mean, I don't know. Is it really necessary? Yes." Y/n huffed. "Brilliant. I owe you." He smiled.
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It had been a few weeks since the conversation with Regulus. Y/n and Regulus met up every few days so Y/n could give Regulus insider information. It was mainly just pranks they were planning, or different ways to make Snape's life a living hell. But Y/n had told Regulus nothing about Remus' condition. As much as she loved him, she knew that was too far.

The more the two met, the more Regulus began to like Y/n. They had passed the friends stage and now were good friends. 

As for the marauders, James, Remus, and Peter had their doubts but they saw how happy it made her and they were happy for her. Sirius, on the other hand, was very against it. He begged y/n to stop. He even said that he would date her himself.
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"And so Sirius had cursed Snape for the entire week so whenever he tried to say something bad, he would say, like, pink sparkles or something." Y/n snickered. Regulus watched her with a glimmer in his eye. He had officially given up on restricting his feelings. He was totally, undeniably in love.

"I need to admit something to you." Regulus blurt. "What?" Y/n asked, her smile momentarily fading. "I'm- I fancy you." Regulus admit. Y/n let out a snicker. "You're a right git, Reg."

"I'm not kidding, y/n." Regulus scolded. "At first I was using you, I'm going to be honest. But now- now I think I love you." Regulus muttered. "Wait. Using me?" Y/n asked. She was no longer laughing. "Yes. But not anymore, I swear!" Reg defended. "Are you kidding me? You knew how much I love you and you decided to manipulate me so I would tell you about my best friends? I betrayed them! That's the worst thing someone could do." Y/n sneered. "That's how it began. But it's so much more than that now!" Regulus assured. "You prat! I've got to go apologize to the boys. Have fun finding another spy you smiley scum." Y/n snapped, abruptly standing up and storming off.