The Darkest Days - (Malec)

Introduction

This takes place in the Thule version of the Earth, bringing out Magnus' and Alec' life in Thule. Thule is a world where, due to the blight , no magic except for those of the demonic nature works.

Due to the absence of angelic magic, the tools and runes the Shadowhunters rendered were slowly becoming powerless.

Not only the Shadowhunters, but also the Warlocks were affected. All the Warlocks, except for half-shadowhunter Tessa Grey, began to get ill and slowly turn into demons.

I suggest you read this only after you read Queen of Air and Darkness.

Reading Red Scrolls of Magic would help for enjoying the Epilogue better.