Dungeon Master's Guide
The Dungeon Master's Guide is the ultimate tool every Dm needs to bring life to their world.
You are the DM and it's up to you to make your universe the most exciting possible. The Dungeon Master's Guide will help you to achieve that goal by providing you with new rules and new possibilities.
If you need magic item, don't look further. A complete list of magic item, going from the common Magic Weapon +1, to legendary weapon such as Wawe is available. You will even find rule to create your own sentient magical object.
The Dungeon Master's Guide will also provide you with world buildings tool such as option for your evil NPC, motivation for them, motivation for your own adventuers and many more.