Quests:

Necrasphodel Flowers - accessible from level 3
Galmakhar's Helmet - accessible from level 4
Lingraonts the Mage's Crown or Lingraonts the Mage's Enchanted Crown - accessible from level 5

Reputation:
Hunters of the Undead accessible from level 3

Quests can be received from Shiko the Paladin  Tomb of Kings or the  Royal Tomb.

You can also obtain rewards for increased reputation from him.

The key gives you the choice of unlocking the Silent or Singing chamber.

Singing chamber – inside you will find chess pieces and after collecting a certain number you can exchange them them in your backpack (Backpack - Collection - Chess).

Silent chamber – inside you will find items from green sets 1-5.

Note! The items obtained from the Silent chamber will have reduced durability compared to the equipment obtained from monster drops.

From the hiding places you can obtain:

You can also obtain various elixirs. But be careful - sometimes when searching the hiding place, you can get attacked by a monster!

You can find Necrasphodel in the Derelict House. Their location can be found on the map below.

As you progress through the instance, you will receive fragments of the collection. Having collected all the necessary elements, you can get the Mage Treasure.