How to fit a detail in a paragraph???

Hi!! I've been writing my essay and I'm stuck because I'm not sure where to fit a detail in a paragraph.

So initially what I wrote was

"Despite the difference in personality, Harris and Klebold’s shared frustration became the basis of their toxic friendship. At the start of a high school year at Columbine High School, Harris had moved to Littleton. There, he eventually met Klebold, and their friendship began. Together, they created a rebellious social group, the Trench Coat Mafia, which led to their bullying. Their friendship grew stronger with their shared hate for the society around them (“Eric Harris”), caused by how excluded they felt in their school community as well as the bullying they went through (Briggs). Additionally, Klebold struggled mentally with his inner emotions (“Dylan Klebold”). Their twisted belief in revenge and violence against those who hurt them strengthened as their frustration increased."

Then I felt like I had to add their actual personality since that's basically what this paragraph is about; the difference between their traits (" Harris was commonly described to be charismatic and manipulative, with certain degrees of intensity (“Eric Harris”), while Klebold was more reserved and frequently emotional."). I added it different places but most of it seems wrong so I'm not sure what to do. Give me feedbacks on how I can fit it in there please!