Louis and Lyra

This explains the relationship between Louis Robinson and Lyra Robinson.
==Original Universe==
Louis and Lyra are brother and sister, and they have a great connection with each other. They are almost four years apart. Though they clearly look like siblings, their personalities could not be any more different. They often get into fights about several small things, but in the end they always love each other.
Life for Louis was very lonely before his parents had another child. When Lyra was born in 2004, Louis was disappointed that the baby was a girl and not a boy. However, he loved his little sister very much, and always spent time to play with her. When he was a toddler, he used to always carry Lyra around like a football and run around the house, which they both enjoyed very much. Oftentimes they play soccer with each other and try to see who's better.
As Lyra grew up, there was no boy in the world who could be like her big brother. She would always want to be around him and his friends and be a part of his world. However, as she grew into the double digits, he started to distance herself from him, which made her very sad. Lyra had trouble making friends in her school, and often got jealous of how Louis has his core group while she is struggling.
Several people at Lyra's school know her as Louis's little sister, and expect her to be just like him. However, she tried so hard to prove that she was not like him at all. While Louis was more relaxed and didn't care about school, Lyra tried her hardest and put school first. She was told by her coach that she was far better than Louis at soccer, but the only thing that made her worse is the age gap and experience.
Whenever Louis brings his friends over to hang out at his house, Lyra usually ends up hanging out with them. They all got used to her and like her, but Louis found it very annoying. Lyra's favorite out of his friends was definitely Zack, because she thought he was the most attractive out of all of them.
When she was thirteen, she asked her brother that she might like girls. He was completely shocked, and made mocked her about it for weeks, until she finally came out as bisexual, which he completely supported and helped her. He was very impressed when she met her girlfriend, Phoebe. 
When Lyra and Phoebe were together, she would tell her brother about everything. He often questioned if her sexuality was "just a phase" and if she would "just go back to liking guys". This became a fight, and their mother became annoyed at her son for his "homophobia". After they broke up, Lyra had nobody to turn to except for her brother. She came to him for the next couple of weeks, and he was her shoulder to cry on. He then apologized for making her feel uncomfortable. 
When Louis and Marmalade broke things off, Lyra also broke things off with her. Anytime he would bring her up, she would call her a "cheating whore", and their mother caught onto this trend shortly after. After they made amends, Lyra still wouldn't hold back. When she found out about Marmalade's suicide attempt and how close she was to passing away, Lyra still wouldn't budge. She asked why he would save her, only for him to reply, "You're too young, you wouldn't understand".  
Lyra pointed out that Marmalade was the source of his change of character. Before her, Louis was more playful, more energetic, and overall more fun to be around. He told her that it's just a part of growing up. She then said that both of their love lives always end up with them fighting over it. Louis agreed. When Marmalade returned from the ward, Lyra apologized for being rude to her for that year. 
After finding out that Lyra started dating Nick's younger brother, he told her to be careful. He wasn't bothered by the fact that they had sex, but whenever Nick would bring it up, it would irk him.