UPDATE 22 Jul 2021- reread as an adult and it still holds up. This is the epitome of YA fantasy. also this trilogy are the only good cassandra clare books.

****sorta mild spoliers****
This is probably my favorite Cassandra Clare book ever.
I usually dislike how Cassandra Clare wraps up her books. She hits the climax about 2/3 into the book and then summarizes and sets up the next book in rest of it leaving some not so exciting reading that usually feels like a bit of a hassel. This book was the same but what makes it stand out is the fact that it concluded the series so the summarizing and wrapping up was important. The epilogue at the end was my very favorite thing. It was my favorite part of the entire book. In the epilogue it displayed how love lasts longer and is the same over time. Within that one epilogue I cried, laughed, and smiled along with the characters. Within that one epilogue I lived and loved and died. That epilogue could have been its own book it was so great. It was sorta perfection.
I love the love triangle and how it is not a normal love triangle. The three involved are tragic in their own way but not in the fact of choosing one over the other. I love how they all love each other and can coexist with each other and with each others' love. I love that there are no "teams" and that it is both because both is good. I love how they all sacrifice things in the name of love but then again they don't.(read it to understand it man)
I love the constant references to classical literature specifically A Tale of Two Cities and the references to different landmarks and architecture.
I love the character development of Will. How he goes through a change in each book slowly melting his heart and displaying his love completely transforming by the end of the series. I love the character development of Jem and how he is ever facing a new challenges and overcoming them and staying strong. I love the character development of Tessa because she was this timid American girl and then became this awesome head-strong book-loving gets-what-she-wants girl who gets all dem guys amirite? I love the plot twists and changes that they all inovatively overcome and stay strong throughout.
I love all the story lines of all the other amazing characters and how you genuinely care for every single person in this amazing world.
And last but not least, the book jacket is also really amazing because there is a freAKIN FAMILY TREE ON THE INSIDE LIKE YES GENEALOGY AMIRITE ???!!! #familylineageismyish and it also was very helpful and explanatory.
It goes through all the sorrows and joys of life.

You read books and you live a thousand lives but usually its a percentage of one or two lives but this book was at least 25 lives...or at least thats how it felt?