This collection started fine and went downhill.

We are supposed to be experiencing Simon's path in becoming a shadowhunter, and his adventures in the academy, but we get instead a bunch of stories from other characters mostly as a fan sevice. I liked some of those stories but in focusing on that we don't get any development of this new Simon and his new friends. Most of their interactions and growth happens off screen, we don't see them. In one story he isn't friends with anyone but George, in the next story he has more friends out of nowhere. Two year pass and we only get glimpses of his actual time in school.

Simon was one of my favorite character in this universe, but this one is whiny, angsty and extremely insecure. There were nothing interesting about him. This collection lost the opportunity to develop him beyond a side comic relief character. We got George Lovelace, who is basically Simon from previous books, aka the friend and comic relief, and he was the only character I cared about.

Spoiler

So I don't understand the choice of killing him, beyond manipulating us into feeling something the book didn't achieved through 9 stories. I was sad for George but I wasn't devastated because even though I liked him, I wasn't interested in this story that much.

I rated each story like this:

Welcome to the shadowhunter academy 3/5
The lost Herondale 3/5
The whitechapel fiend 2.5/5
Nothing but shadows 3.5/5
The evil we love 3.5/5
Pale kings and Princes 2/5
Bitter of tongue 2.5/5
The fiery trial 1/5
Born to endless night 1/5
Angels twice descending 1/5

If you are a super fan of the shadowhunter world, go ahead and give this a try, I would recommend the audiobook. But if you don't read it, you aren't missing much.

This collection spoil the mortal instruments and the infernal devices. It not essential to read before the dark artifices.